616 


JC-NRLF 


C    a    T3S    533 


GIFT  OF 
Charles  L.   Camp 


EARTH 


MEMOIRS 


or  Tin: 


CARNEGIE  MUSEUM. 

VOL.  I.  NO.  3. 


THE  OSTEOLOGY   OF  THE   STEGANOPODES. 
BY  R,  W.  SHUFELDT,  M.D. 

At  the  present  writing  it  is  a  little  over  nineteen  years  ago  since  I  first  paid  any 
attention  to  the  osteology  of  the  steganopodous  birds.  My  initial  paper  upon  this 
subject  was  a  brief  one  devoted  to  the  osteology  of  Phalacrocorax  bicristatus  (Science, 
Vol.  2,  No.  41,  Nov.  16,  1883,  pp.  640-042,  3  figs.).1  The  figures  illustrating 
that  paper  have  since  been  used  in  text-books  on  ornithology  and  zoology  to 
Home  extent.  As  will  be  observed  in  the  body  of  the  present  memoir,  five  years 
later  I  published  another  contribution  to  this  subject,  entitled  "Observations  upon 
the  Osteology  of  the  Orders  Tubinares  and  Steganopodes"  (Proc.  U.  S.  Nat.  Mus., 
Vol.  XL,  1888,  pp.  253-315,  43  figs,  in  text);  and  also  in  January,  1889,  "Notes  on 
Brewster's  and  the  Blue-footed  Gannet"  (The  Auk,  Vol.  VI.,  No.  1,  p.  67).  What 
I  have  done  in  the  matter  of  fossil  birds  of  this  suborder,  will  be  chiefly  found  in 
my  memoir,  "  A  Study  of  the  Fossil  Avifauna  of  the  Equus  Beds  of  the  Oregon 
Desert"  (Jour.  Acad,  Nat.  Sci.  Phila,,  Vol.  XL,  Pis.  XV.-XVII,  (4to),  Phila,  Oct.,  1892, 
pp.  389-425),  and  a  number  of  abstracts  of  the  same,  subsequently  published  else- 
where, as  in  The  American  Naturalist,  and  The  Auk.  In  1894,  in  the  Proceedings  of 
the  Zoological  Society  of  London,  I  published  a  brief  paper  "  On  the  Affinities  of 
the  Steganopodes"  (Feb.  20,  pp.  160-162),  and  in  the  Ills  of  the  same  year,  in  a 
paper  entitled  "  On  Cases  of  Complete  Fibula;  in  Existing  Birds,"  made  a  study  of 
the  fibula  in  the  Sulidx  (Vol.  VI.,  No.  23,  London,  July,  1894,  Art.  XXIX.,  pp.  361- 
366,  figs.  1,  2).  The  Auk  also  published  a  paper  of  mine  In  October^  Tr>f)4,  making 

1  See  also  ibid.,  p.  822  ;  also  Vol.  III.,  No.  53,  Feb.  8,  1884,  p.  143  ;  also  a  rejoinder  to  Dr.  Theo.  N.  Gill,  ibid.,  III. 
No.  63,  pp.  474,  475,  Apr.  18,  1884. 

109 


89O420 


11.0.  MEMOIRS   OF   THE    CARNEGIE   MUSEUM 

•  •  • 
.  •  •  • 
•  *  *•  • 

certain  references  to  these  birds,  it  being  entitled,  "  Notes  on  the  Steganopodes  and 
^•'•Ffcfeil  Birds'  Eggs"  (Vol.  XL,  No.  4,  pp.  337-339) ;  and  there  was  likewise  a  note 
published  about  them  on  November  6,  1894  (P.  Z.  S.,  p.  608). 

Since  then  and  up  to  the  present  time,  (October,  1902),  no  paper  or  publica- 
tion of  any  importance  whatever  of  mine  has  been  published  about  the  Steganopodes, 
and  especially  about  their  osteology.  In  this  interim,  however,  I  made,  as  far  as 
the  material  at  hand  would  permit  me,  a  more  or  less  extensive  study  of  the 
osteology  of  the  entire  group.  These  researches  from  time  to  time  were  written  out 
and  with  them  incorporated  the  facts  brought  out  in  my  earlier  publications.  As 
time  passed  on,  too,  Mr.  F.  A.  Lucas,  of  the  U.  S.  National  Museum  at  Washington, 
published  a  number  of  very  important  and  interesting  papers  on  the  osteology  of 
the  Steganopodes,  and  as  two  of  the  best  of  these  were  of  no  great  length,  they  like- 
wise, with  their  figures,  are  herewith  incorporated. 

Moreover,  during  the  last  seven  or  eight  years,  Mr.  Lucas  with  great  industry  has 
collected  together  for  the  osteological  collections  of  the  U.  S.  National  Museum  the 
finest  series  of  skeletons  of  steganopodous  birds  existing  anywhere  in  any  institution 
in  the  world.  With  great  courtesy  and  marked  generosity  Mr.  Lucas  has  placed  all 
this  material  at  my  disposal,  to  be  studied  and  utilized  in  the  present  connection, 
and  for  this  and  for  many  other  favors  in  the  same  direction,  altogether  too 
numerous  to  mention,  my  most  sincere  thanks  are  due  to  that  distinguished  anat- 
omist. I  am  greatly  indebted,  too,  to  the  courtesy  of  the  U.  S.  National  Museum  in 
allowing  me  to  take  to  my  residence  in  Washington,  from  time  to  time,  specimens 
to  be  photographed  by  me,  which  latter,  being  reproduced,  form  the  material  repre- 
senting many  of  the  figures  in  my  plates.  My  private  collections  have  likewise 
furnished  specimens  not  as  yet  existing  in  the  U.  S.  National  Museum,  and,  as  will 
be  seen,  a  number  of  these  will  also  be  found  among  my  figures  on  the  plates.  I 
am  also  indebted  to  other  persons  who  have  kindly  collected  material  for  me,  but 
I  believe  in  each  case  such  assistance  is  duly  noticed  in  the  body  of  the  present 
memoir.  It  also  gives  me  pleasure  to  extend  my  thanks  to  my  wife  Alfhild  for 
having  made  a  very  fair  and  correct  copy  of  the  notes  I  have  collected  on  the 
osteology  of  the  Steganopodes  for  a  number  of  years  past,  and  these  may  now  be 
presented  in  the  following  manner  : 

We  have  this  suborder  of  birds  very  fully  represented  in  the  North  American 
avifauna.  Of  the  first  family  in  it  to  be  considered  in  this  memoir,  —  the  Phaethon- 
6rTropic~Birdc>we  have  at  least  two  good  species,  viz:  —  Phaethon  flavirostris, 
the  Yellow-billed  Tropic  Bird,  and  P.  sethereus,  the  Red-billed  Tropic  Bird.  Gannets 
of  the  family  Sulidx  are  still  raore  numerous,  but  they  all  belong,  apparently,  to  the 


SHUFELDT:   THE  OSTEOLOGY  OF  THE  STEGANOPODES  111 

genus  Sula.  There  is  S.  cycmojw,  8.  mla,  S.  brewsteri,  S.  gossi,  S.  piscator,  and  finally, 
the  well-known  Gannet  Sula  bassana.  The  Anhingidss  or  Darters,  are  represented 
by  the  common  Anhinga,  or  Snake  Bird,  (Anhinga  anhinga).  Ornithologists  have 
placed  all  our  Cormorants  in  the  genus  Phalacrocorax,  (Phalacrocoracidse),  and  of 
them,  species  and  subspecies  taken  together,  there  seem  to  be  nearly  a  dozen  vari- 
eties. Next  we  have  three  Pelicans  of  the  family  Pelecanidx;  these  are  Pelccanus 
erytkrorhynchus,  the  American  White  Pelican;  P.  fuscus,  the  Brown  Pelican;  and 
lastly,  P.  californicus,  the  Californian  Brown  Pelican.  Finally,  there  is  the  Man- 
o'-War  Bird,  Fregata  aquila  of  the  family  Fregatidse,  —  a  conspicuous  steganopod 
of  tropical  and  subtropical  coasts  generally. 

Newton  has  said  "that  the  tropic  birds  form  a  distinct  family,  Phaethontidx,  of 
the  Steganopodes  (the  Dyspowmorphss  of  Professor  Huxley),  was  originally  maintained 
by  Brandt,  and  is  now  generally  admitted,  yet  it  cannot  be  denied  that  they  differ 
a  good  deal  from  the  other  members  of  the  group  ; 2  indeed,  Professor  Mivart,  in  the 
Zoological  Transactions  (X.,  p.  364)  will  hardly  allow  Fregata  and  Phaethon  to  be 
Steganopodons  at  all ;  and  one  curious  difference  is  shown  by  the  eggs  of  the  latter, 
which  are  in  appearance  so  wholly  unlike  those  of  the  rest.  The  osteology  of  two 
species  has  been  well  described  and  illustrated  by  Professor  Alph.  Milne-Edwards 
in  M.  Grandidier's  fine  Oiseaux  de  Madagascar  (pp.  701-704,  pis.  279-281  a)."3 

The  same  distinguished  authority  has  remarked  of  the  Sulidse  that  "  structurally 
the  Gannet  presents  many  points  worthy  of  note,  such  as  its  closed  nostrils,  its 
aborted  tongue,  and  its  toes  all  connected  by  a  web  —  characters  which  it  possesses 
in  common  with  most  of  the  other  members  of  the  group  of  birds  (Steganopodes)  to 
which  it  belongs.  But  more  remarkable  still  is  the  system  of  subcutaneous  air-cells, 
some  of  large  size,  pervading  almost  the  whole  surface  of  the  body,  communicating 
with  the  lungs,  and  capable  of  being  inflated  or  emptied  at  the  will  of  the  birds 
This  peculiarity  has  attracted  the  attention  of  several  writers — Montagu,  Professor 
Owen,  (Proc.  Zool.  Soc.,  1831,  p.  90),  and  Macgillivray ;  but  a  full  and  particular 
account  of  the  anatomy  of  the  Gannet  is  still  to  be  desired." 

Some  of  our  Sulidse,  as  S.  sula,  S.  cyanops,  and  Sula  piscator  are  known  as  Boo- 
bies, from  their  apparent  excessive  stupidity,  but  which  the  writer  pleases  to  call  too 
little  dread  or  fear  of  the  great  destroyer  —  man.  Sailors  are  very  prone  to  the 
taking  of  bird-life  without  stint  and  for  no  other  purpose  than  amusement,  when- 
ever they  get  the  opportunity  upon  lonely  islands  where  sea-fowl  abound.  Myriad. 

1  Sulidic  (Gannet),  Pelecanidx  (Pelican),  Plotidie  (Snake- Bird),  Phalacrocoracidie  (Cormorant),  and  Fregalida; 
( Frigate-Bird ). 

•Newton,  Al.,  F.R.S.     Art.  "  Tropic-Bird,"  Encycl.  Brit.,  9th  Ed.,  Vol.  XXIII.,  p.  588,  1888. 


112  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

of  Penguins  and  Gannets  have  thus  perished.  Superficially  a  Booby  is  distinguished 
from  a  Gannet  in  that  the  former  lacks  the  median  stripe  of  naked  skin  over  the  re- 
gion of  the  throat,  so  characteristic  of  the  latter  birds.  As  a  rule,  too,  Boobies  are 
tropical  species,  and  breed  in  trees,  and  are  of  wide  distribution. 

Morphologically,  the  genus  Anhinga  has  received  more  attention  than  any  other 
of  the  Steganopods.  "  Beside  the  excellent  description  of  the  American  bird's  ali- 
mentary canal  furnished  to  Audubon  by  Macgillivray,  other  important  points  in  its 
structure  have  been  well  set  forth  by  Garrod  and  Forbes  in  the  Zoological  Proceed- 
ings (1876,  pp.  335-345,  pis.  XXVI.-XXXIIL;  1878,  pp.  679-681  ;  and  1882,  pp. 
208-212),  showing  among  other  things  that  there  is  an  appreciable  anatomical  dif- 
ference between  the  species  of  the  New  World  and  of  the  Old ;  while  the  osteology 
of  P.  melanogaster  has  been  admirably  described  and  illustrated  by  Professor  Milne- 
Edwards  in  M.  Grandidier's  great  Oiseaux  de  Madagascar  (pp.  691-695,  pis.  284-285). 
In  all  the  species  the  neck  affords  a  feature  which  seems  to  be  unique.  The  first  seven 
of  the  cervical  vertebrae  form  a  continuous  curve  with  its  concavity  forward,  but  the 
eighth  articulates  with  the  seventh  nearly  at  a  right  angle,  and,  when  the  bird  is  at 
rest,  lies  horizontally.  The  ninth  is  directed  downwards  almost  as  abruptly,  and  those 
which  succeed  present  a  gentle  forward  convexity.  The  muscles  moving  this  curi- 
ous framework  are  as  curiously  specialized,  and  the  result  of  the  whole  piece  of 
mechanism  is  to  enable  the  bird  to  spear  with  facility  its  fishy  prey."  (Newton,  Arts 
"  Gannet,"  and  "  Snake-Bird,"  loc.  tit..,  p.  188. 

Again  we  find  the  same  eminent  ornithologist  under  the  article  "  Frigate-Bird" 4 
declaring  that  that  interesting  Steganopod  "was  placed  by  Linnaeus  in  the  genus  Pel- 
ecanus,  and  until  lately  its  assignment  to  the  family  Pelecanidne  has  hardly  ever  been 
doubted.  Professor  Mivart  has,  however,  now  declared  (Trans.  Zool.  Soc.,  X.,  p. 
364)  that,  as  regards  the  postcranial  part  of  its  axial  skeleton,  he  cannot  detect  suf- 
ficiently good  characters  to  unite  it  with  that  family  in  the  group  named  by  Pro- 
fessor Brandt  Steganopodes.  There  seems  to  be  no  ground  for  disputing  this 
decision  so  far  as  separating  the  genus  Fregata  from  the  Pelecanidse  goes,  but  sys- 
tematists  will  probably  pause  before  they  proceed  to  abolish  the  Steganopodes,  and 
the  result  will  most  likely  be  that  the  Frigate-Birds  will  be  considered  to  form  a 
distinct  family  (Fregatidse)  in  that  group.  In  one  very  remarkable  way  the  oste- 
ology of  Fregata  differs  from  that  of  all  other  birds  known.  The  furcula  coalesces 
firmly  at  its  symphysis  with  the  carina  of  the  sternum,  and  also  with  the  coracoids 

*  "  '  Man-of-War  Bird  '  is  also  sometimes  applied  to  it,  and  is  perhaps  the  older  name,  bnt  is  less  distinctive,  some 
of  the  larger  Albatrosses  being  so  called,  and,  in  books  at  least,  has  generally  passed  out  of  use."  [Man-o'-\var  Bird  is 
the  vernacular  name  given  to  this  species  in  the  A.  O  U.  Check-list  of  North  American  Birds,  and  is  the  one  in  com- 
mon use  by  ornithologists  in  the  United  States.] 


SHUFELDT  :     THE   OSTEOLOGY    OF   THE   STEGANOPODES  113 

of  the  upper  extremity  of  each  of  its  rami,  the  anterior  end  of  each  coracoid  coales- 
cing also  with  the  proximal  end  of  the  scapula.  Thus  the  only  articulations  in  the 
whole  sternal  apparatus  are  where  the  coracoids  meet  the  sternum,  and  the  conse- 
quence is  a  bony  framework  which  would  be  perfectly  rigid  did  not  the  flexibility 
of  the  rami  of  the  furcula  permit  a  limited  amount  of  motion.  That  this  mecha- 
nism is  closely  related  to  the  faculty  which  the  bird  possesses  of  soaring  for  a  consid- 
erable time  in  the  air  with  scarcely  a  perceptible  movement  of  the  wings  can  hardly 
be  doubted,  but  the  particular  way  in  which  it  works  has  yet  to  be  explained  "  (loc. 
clt.,  Vol.  IX.,  p.  786). 

Among  others,  the  birds  we  propose  to  consider  osteologically  in  the  present 
memoir  constitute  the  ORDER  STEGANOPODES  of  the  Check  List  of  the  American 
Ornithologists'  Union  (1886,  p.  106),  where  they  are  divided  into  the  families  Phae- 
thontidse,  Sulidse,  Anhingidse,  Phalacrocoracidss,  Pelecanidw,  and  Fregatidx,  —  a  family 
arrangement  adopted  here.  According  to  Reichenow  the  "  Steganopodes  "  are  an 
Order  (IV.)  of  the  NATATORES,  and  contain  but  three  families,  the  Graculidse> 
Sulidte,  and  Pelecanidte?  while  Dr.  Stejneger  arrays  them  as  follows : 

Order  X.  Superfamily.  Family. 

Pelecanidre. 
Sulidse. 


STEGANOPODES. 


(XVI.)  Pelecanoidete. 


PhalacrocoracidaB. 


Anhingidse. 
(XVII.)  Fregatoideas. 

(XVIII.)  Phffitontidea?. 

Professor  Fxirbringer,  in  his  great  work,  places  the  "  Steganopodes  "  (a  Gens)  in 
his  Suborder  Ciconiiformes,  of  the  Order  PELARGORNITHES,  and  divides  them  into  the 
four  families  Phadhontidss,  Phalacrocoraddss,  Pelecanidse,  and  Fregatidx.  A  still  dif- 
ferent arrangement  is  proposed  by  Mr.  Seebohm,  and  the  place  they  are  supposed  to 
occupy  in  the  system  according  to  his  views  will  later  on  be  given  by  me  in  my 
Osteology  of  the  Tubinares. 

Garrod  has  said  "  The  Steganopodes,  which  do  not  form  so  natural  a  family,  in 
my  eyes,  as  in  those  of  many  ;  for  their  myological  formula  is  not  the  same  in  all, 
being 

In  Phsethon  A.  XY, 

In  Sula  and  Phalacrocorax  AX, 

In  Fregata  A, 

•Die  Vogel  der  Zoologiscben  Garten,  1882. 


PELECANIFORMES. 


Phalacrocoraces  - 


114  '   MEMOIRS   OF   THE    CARNEGIE    MUSEUM 

from  which  it  may  be  inferred  that  Phaethon  approaches  the  Ciconiidas  and  Fregota 
the  Accipitres.  They  all  possess  the  ambiens,  caeca,  a  tufted  oil-gland,  and  the  four 
toes  included  in  a  web,  which  is  but  imperfectly  developed  in  some.  Sida  and 
Phalacrocorax,  with  Plotus,  form  one  family,  Phaethon  another,  Fregata  a  third,  and 
Pelecanus  a  fourth."  (Coll.  Sci.  Mem.,  p.  221.) 

Dr.  Sharpe  does  not  concur  in  this  opinion,  and  in  his  "  A  Review  of  Recent 
Attempts  to  Classify  Birds"  (Budapest,  1891)  places  this  group  betwixt  the  Anseri- 
formes  and  the  Cathartidiformes,  thus  : 

Order  (XXIII.)         Suborders.  Families. 

Phaethontes  -    -    -  Phaethontidse. 
Sulse    ------  Sulidte. 

f  Phalacrocoracidse. 

1  Plotidse. 

Pelecani     -    -    -    -  Pelecanidse. 
Fregati Fregatidee. 

In  volume  I  of  his  "  Hand  List"  (page  232),  recently  issued,  this  arrangement  is 
somewhat  changed.  There  the  Pelecaniformes  stand  between  the  Ichthyornithi- 
formes  (Order  XXII.)  and  the  Cathartidiformes  (Order  XXIV.).  They  are  then 
divided  into  the  eight  following  families,  viz.:  1.  Phalacrocoracidse.  2.  Odonto- 
pterygidse.  3.  Plotidse.  4.  Sulidse.  5.  Fregatidse.  6.  Phaethontidse.  7.  Pele- 
canidse.  8.  Pelagornithidse.  Of  these  2  and  8  are  extinct  groups  (1899). 

Nearly  a  quarter  of  a  century  before  Sharpe's  work  appeared  Huxley  in  his  P. 
S.  Z.  memoir  (1867)  had  placed  the  steganopods  in;his  group  Dysporomorphse  of  the 
Desmognathse,  and  had  said  of  them  :  "  The  rostrum  is  long  and  pointed  and  more 
or  less  curved,  and  the  external  nasal  apertures  are  very  small.6  There  are  no  basi- 
pterygoid  processes.  The  palate-bones  unite  for  a  considerable  distance  behind  the 
posterior  nares,  and  send  down  a  vertical  crest  from  their  junction." 

"  The  maxillo-palatines  are  large  and  spongy.  The  angle  of  the  mandible  is 
truncated.  The  sternum  is  broad,  and  its  truncated  posterior  edge  is  either  entire 
or  has  a  shallow  excavation  on  each  side  of  the  middle  line. 

"  The  hallux  is  turned  forwards  or  inwards,  and  is  united  by  a  web  with  the 
completely  webbed  anterior  toes.  The  ratio  of  the  phalanges  is  as  in  the  preceding 
genera. 

"  The  oil-gland  is  surmounted  by  a  circlet  of  feathers. 

6  They  are  now  known  to  be  entirely  absent  in  some  of  the  genera  as  Sula  and  others. — S. 


SHUFELDT  :    THE   OSTEOLOGY    OF   THE   STEGANOPODES  115 

"This  group  answers  to  the  ' Steganopodes '  of  Illiger;  and  since  the  appear- 
ance of  the  admirable  memoir  of  Brandt,  '  Zur  Osteologie  der  Vogel,'  in  1840,  no 
doubt  can  have  been  entertained  as  to  its  extremely  natural  characters.  The  genera 
composing  it  are  sharply  divided  by  the  structure  of  the  skull,  described  above,  into 
two  groups  —  the  one  containing  the  Pelicans,  the  other  the  remaining  genera" 
(pp. 461-462). 

Doctor  Hans  Gadow  makes'an  Order  9  —  the  Procellariiformes,  and  an  Order  11, 
—  the  Falconiformes,  —  between  which  he  places  his  Order  10,  —  the  Ardeiformes. 
These  last  are  thus  characterized  : 

10.  ARDEIFORMES. 

Cosmopolitan  Aquatic. 
Young  passing  through  a  downy  stage. 
Oil-gland  tufted.     Aquito-cubital. 
Humero-coracoid  deep.     No  ectepicondylar  process. 
Desmognathous.     No  basipterygoid  processes. 

I.  STEGANOPODES. 

Cosmopolitan.     Aquatic-nidicolous. 

Piscivorous. 

Rhamphotheca  compound.     Nares  impervious. 

No  supraorbital  glands.     Angulare  truncated. 

Neck  without  apteria. 

Legs  short ;  all  the  four  toes  webbed  together.     (Unique.) 

Hypotarsus  complex.     Flexors  type  of  II. 

Orthoccelous  type  II.     Tongue  rudimentary. 

1.  Phaetontidse. 

15  cervical  vertebrae. 
Procoracoid  process  large. 
Garrod's  symbol  AXY  +  . 

2.  Phalacrocoratidte  (including  Sulinse,  Plotinse,  Phalacrocoracinse). 

18-20  cervical  vertebrae. 
Garrod's  symbol  AX  +  . 

3.  Pelecanidse. 

17  cervical  vertebrae. 
Procoracoid  process  small. 
Garrod's  symbol  A  +  . 


116  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

4.  Fregatidse. 

15  cervical  vertebrae. 
Procoracoid  process  small. 
Garrod's  symbol  A  +  . 

II.  HERODII. 

Cosmopolitan.     Waders.     Nidicolous. 

Zoophagous.     Bill  long,  pointed,  laterally  compressed,  with  simple  rham- 

photheca.     Nares  pervious. 
No  supraorbital  glands. 
Neck  long,  with  long  apteria. 

Downs  of  adults  only  upon  the  apteria.     (Unique  among  Ardeiformes.) 
Legs  long  ;  four  toes  not  webbed. 
Hypotarsus  complex.     Flexors  of  type  I.  or  VII. 
Orthocoelous.     Type  II.     Caeca  rudimentary. 
Tracheo-bronchial  muscles  attached  to  second  bronchial  rings. 

1.  Ardeidse. 

19  or  20  cervical  vertebrae. 

Several  pairs  of  powder-down  patches. 

1 1  primaries.  —  Cosmopolitan. 

2.  Scopidse. 

16  cervical  vertebrae. 

No  powder-down  patches. 
10  primaries.  —  Ethiopian. 

III.  PELARGI. 

Cosmopolitan.     Waders. 
Neck  long,  without  apteria.     Nares  pervious. 
Rhamphotheca  simple. 
Legs  long.     Hypotarsus  simple. 
Intestinal  type  IV.  telogyrous. 
1.   Ciconiida;. 

Zoophagous.     Nidicolous. 

17  cervical  vertebrae. 
Hallux  long,  toes  not  webbed. 
Flexors  of  type  I. 

Tongue  rudimentary. 

Caeca  rudimentary. 

Syrinx  without  Tracheo-bronchial  muscles. 


SHUFELDT  :     THE    OSTEOLOGY    OF    THE   STEGANOPODES 


117 


2.   Phcenicopteridse. 

Tropical.     Nidifugous. 

18  or  19  cervical  vertebrae. 

Hallux  small,  front  toes  webbed.     Flexors  of  type  IV. 

Tongue  large  and  thick. 

Cseca  functional. 

Syrinx  with  tracheo-bronchial  muscles. 

In  1889,  as  has  b3en  stated  above,  the  present  writer  contributed  some  brief 
"Observations  upon  the  Osteology  of  the  Orders  Tubinares  and  Steganopodes "  to 
the  Proceedings  of  the  U.  S.  National  Museum  (pp.  286-314),  and  so  far  as  the 
steganopodous  birds  were  concerned  there  appeared  in  that  article  an  illustrated 
account  of  the  skeleton  of  Sida  bassana;  some  remarks,  also  with  figures,  on  the 
osteology  of  Cormorants  and  the  Brown  Pelican.  That  paper,  with  its  figures, 
will  be  incorporated  into  the  present  memoir,  but  at  this  writing  I  am  better  off  for 
osteological  material  wherewith  to  render  a  description  of  the  skeletal  characters  of 
this  suborder.  My  observations  at  this  time  are  based  principally  but  by  no  means 
altogether  upon  a  study  of  the  following  skeletons  and  parts  of  skeletons. 

LIST  OF  MATERIAL. 


Name. 


Phaethon  flavirostris. 
Phaethon  sethereus. 

Sula  bassana. 
Sula  piscator. 
Sula  cyanops. 
Sula  gossi. 

Sula  brewsteri. 

Anhinga  anhinga. 
Phalacrocorax  urile. 
Pelecanus  fuscus. 
Pelecanus  fuscus. 
Fregata  aguila. 


Material. 


Remarks. 


Perfect  skeleton. 
Four  perfect  skeletons. 

Skeleton  nearly  complete. 

Skeleton. 
u 

Three  complete  skeletons. 


Skeleton. 

11 

Skull  and  mandible. 
Skeleton. 


No.  17,841.     Smithsonian  collections. 
Author's  collection.     The  gift  of  E.  .1.  Reed 

Esq.,  of  Guaymas,  Mexico. 
No.  16,643.     Smithsonian  collections. 

"     18,739.  "  " 

"     18,542.  " 

Author's  collection.    The  gift  of  E.  J.  Reed, 

Esq.,  of  Guaymas,  Mexico. 
Author's  collection.     The  gift  of  E.  J.  Reed, 

Esq.,  Guaymas,  Mexico. 
No.  18,259.     Smithsonian  collections. 

"     18,982.  "  " 

Author's  collection. 
No.  18,483.     Smithsonian  collections. 

"     18,485.  "  " 


ON  THE  SKELETON  IN  PHAETHON.7 

Of  the  Skull,  etc. — Of  the  two  species  of  Tropic  Birds,  which  we  have  to  consider 
here,  the  red-billed  one  is  the  larger  species,  and  this  difference  is  quite  apparent  in 
their  skulls,  though  in  other  particulars  they  are  very  much  alike.  In  P.  xthereus 

'Dr.  Sharpe,  in  his  recent  Hand-List  of  Birds  (1899,  Vol.  1,  p.  238),  recognizes  the  following  species  of  Phaethon  as 
representing  the  genus  throughout  the  world,  viz  :  P.  rubricnuda,  P.  lepturua,  P.  fulnus,  P.  americanus,  P.  aethereus,  and 
P.  indicm.  In  this  enumeration  P.  americanus  and  P.  flavirostris  are  one  and  the  same  species. 


118 


MEMOIRS   OF   THE    CARNEGIE   MUSEUM 


the  skull  has  an  average  length  of  about  10.8  centimeters,  while  in  the  other  form, 
P.  flavirostris,  it  equals  for  the  same  measurement  but  9.2  centimeters.  Measuring 
from  the  mid-point  of  the  cranio-facial  hinge,  we  find  that  in  the  yellow-billed 
species  the  length  of  the  supero-mandibular  portion  of  the  skull  exactly  equals  in 
length  the  cranial  part,  while  in  P.  xthereus  the  facial  portion  slightly  exceeds  the 
cranial.  Viewed  from  above  (Plate  I.,  Fig.  3),  it  will  be  seen  that  the  supero-man- 
dibular moiety  is  distinctly  marked  off  from  the  cranium  by  the  ver}^  distinct  trans- 
verse cleft  forming  the  cranio-facial  hinge,  which  latter  admits  of  considerable 
mobility  in  the  dried  skull.  The  upper  osseous  bill  is  broad  and  massive  at  its 
base,  but  almost  immediately  tapers  as  we  proceed  anteriorly  towards  its  acute 
apex.  The  culmen  is  slightly  decurved,  while  below  the  latero-external  margins 
are  cultrate.  Just  within  these  there  runs  a  furrow  nearly  to  the  apex,  which  is 
bounded  mesially  by  a  raised  bony  ridge.  Internal  to  this  again,  the  central 
portion,  is  excavated,  from  the  maxillo-palatines  to  the  apex,  being  broad  posteri- 
orly and  gradually  tapering  to  the  front.  A  delicate  medio-longitudinal  ridge 


FIG.  1.     Right  lateral  view  of  the  skull  of  Phaethon  lethereus.     Natural  size.     Drawn  by  the  author  from  a  speci- 
men in  his  own  collection. 

marks  the  anterior  half  of  this  space,  which  is  about  equally  well  marked  in 
the  two  species.  In  these  birds  there  is  always  found  a  small  foramen,  perforating 
the  mandible  upon  either  side,  just  anterior  to  the  lateral  terminations  of  the 
cranio-facial  cleft ;  while  beyond  these,  the  narial  apertures,  one  upon  either  aspect 
of  this  osseous  beak,  are  seen  to  be  of  no  great  size,  being  in  form  elongated, 
ellipsoidal,  communicating,  and  with  smooth,  rounded  margins.  Minute  marginal 
and  culminar  foramina  occur  in  this  part  of  the  skull,  while  the  intervening  surface, 
or  what  is  really  the  sides  of  the  upper  osseous  mandible,  is  delicately  scrolled  over 
with  fine  anastomosing  venations  (Fig.  1). 

The  rhinal  chamber  is  somewhat  capacious,  and  the  hollow  part  of  this  region, 
clear  to  the  apex,  is  more  or  less  filled  in  with  bony  tissue  of  the  cancellous  variety. 


SHUFELDT  :    THE    OSTEOLOGY    OF   THE   STEOANOPODES  119 

The  cranium  is  broad  and  spreading  behind,  and  but  moderately  narrowed 
anteriorly,  and  this  form  defines  the  shape  of  the  superocranial  aspect  of  the  skull, 
where  the  smooth,  rolling  frontal  portion  is  succeeded,  as  we  pass  backwards,  by 
the  flat  and  wide  space  that  separates  the  sharp  marginal  borders  of  the  orbits  above. 
Slight  parial  elevations  characterize  the  parietal  region,  and  this  surface  falls  away 
gradually,  upon  either  side,  towards  the  post-frontal  processes.  Deeply  sculpt,  the 
crotaphyte  fosste  are  mesially  separated  by  a  broad  interval,  smooth  and  unmarked. 
A  remarkable  feature  of  the  skull  of  one  of  these  birds,  and  it  is  still  further 
enhanced  when  the  lower  mandible  is  articulated,  is  the  appearance  it  has  of  having 
been  vertically  truncated  in  the  transverse  plane  or  direction,  or  being  cut  squarely 
across,  reminding  us  of  the  skull  in  certain  Herons  and  their  allies. 

Regarding  the  skull  of  a  Tropic  Bird,  upon  its  lateral  aspect,  we  are  at  first  struck 
with  the  large,  squarish  orbit,  bounded  below  by  the  straight,  stout  zygomatic  bar ; 
posteriorly  by  the  massive  quadrate,  and  the  spreading  post-frontal  process ;  ante- 
riorly, by  the  great,  free  lacrymal  bone,  with  its  projecting  upper  limb,  and  its  ver- 
tical portion,  which  latter  is  twice  perforated  posteriorly  by  conspicuous  pneumatic 
foramina.  The  interorbital  septum  invariably  presents  a  large  quadrilateral  vacuity 
at  its  central  surface,  which  is  usually  distinct  from  the  orbital  foramina  posterior 
to  it.  A  mere  apology  in  bone  represents  the  almost  thoroughly  aborted  ethmoidal 
wing,  or  pars  plana.  The  foramen  for  the  exit  of  an  olfactory  nerve  is  exceedingly 
small  as  it  occurs  upon  the  anterior  wall  of  the  brain-case,  and  the  groove  leading 
from  it  is  open ;  but  the  anterior  foramen  seen  above  the  semi-aborted  pars  plana 
is  of  considerable  size,  and  is  usually  completely  surrounded  by  bone.  In  front,  the 
margin  of  the  rnesethmoid  is  deeply  notched,  being  produced  below  as  a  conspic- 
uous, blunt-pointed  process,  — just  the  reverse,  for  example,  of  what  we  find  in  Sula. 

Turning  to  the  inferior  aspect  of  the  skull  we  meet  with  many  points  of  interest, 
and  a  construction  of  parts  by  no  means  typically  steganopodous  (see  Plate  I.,  Fig.  2). 
In  front  the  maxiUopalatines  are  distinctly  developed,  being  elegant  concavo-convex 
processes,  with  their  convex  sufaces  parallel  with  each  other  but  not  in  contact 
mesially.  Their  concave  external  aspects  are  partially  filled  with  a  very  open  can- 
cellous  tissue  of  bone,  and  they  have  a  broad  base  in  each  case,  which  appears  in 
the  adult  skull  to  coossify  with  the  corresponding  nasal,  maxillary,  and  perhaps, 
premaxillary.  The  postero-inferior  angles  of  the  latter  are,  upon  either  side,  pro- 
duced backwards  as  a  prominent  process  which,  when  the  lower  mandible  is  artic- 
ulated with  the  skull,  outwardly  overlaps  its  margin  opposite  to  them. 

The  palatines,  although  in  contact  for  their  entire  surfaces  in  the  middle  line,  do 
not  coossify  as  is  the  case  in  the  Cormorants,  Gannets  and  other  steganopods. 


120  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

Either  one  of  this  pair  of  bones  is  thickened,  much  cut  away  posteriorly,  but 
broadly  wedged  in  among  the  usual  facial  elements  in  front.  Above  they  are 
moulded  closely  upon  the  rounded  rostrum  of  the  sphenoid,  being  drawn  to  a  fine 
point  anteriorly.  It  is  along  this  line  beneath  that  the  palatines  fuse  with  the 
vomer,  an  element  which  has  much  in  its  form  to  remind  us  of  that  bone  in  the 
Laridse,  being  pointed  in  front,  mesially  carinated  below,  and  grooved  longitudinally 
along  its  upper  surface.  Laterally,  the  surface  of  a  palatine  looks  almost  directly 
outwards,  and  it  is  here  that  we  invariably  find  one  or  more  pneumatic  foramina 
leading  into  the  interior  of  the  bone.  A  palatine  head  is  large  and  offers  an  ample 
articulatory  surface  for  the  corresponding  pterygoid.  These  palatal  heads  are  closely 
pressed  together,  but  in  front  of  them,  below,  the  bones  send  down  in  common  only 
the  merest  suspicion  of  a  midcarination,  a  character  so  common  in  Pelecanus,  Cor- 
morants, and  other  species  of  the  suborder.  The  postero-e'xternal  angle  of  a  pala- 
tine can  hardly  be  said  to  exist  in  the  skull  of  this  bird,  as  the  bone  so  abruptly 
slopes  away  in  that  part  of  its  body,  as  will  be  observed  by  referring  to  the  figures 
in  the  plates. 

The  pterygoids  are  long,  stout,  straight,  subcylindrical,  rod-like  bones,  cupped  at 
their  extremities,  and  when  articulated  in  situ,  stand  well  above  the  basitemporal 
area.  Not  a  semblance  of  such  a  thing  as  a  basipterygoidal  process  is  to  be 
discovered  upon  either  of  them,  or  at  the  anterior  borders  of  the  basisphenoid.  An- 
teriorly, their  palatine  heads  articulate  in  contact  with  each  other  ;  their  divergence 
from  this  point  is  at  an  angle  of  about  20°. 

The  basitemporal  area  is  triangular  in  form  with  a  small  transverse  ridge  cross- 
ing its  center.  In  front  a  broad,  anteriorly  rounded  lip  of  bone  underlaps  the 
double  openings  for  the  internal  carotid.  So  prominent  in  Sula,  the  paroccipital 
processes  are  here  much  reduced  in  size,  and  the  hemispherical  condyle  is  sessile  and 
unnotched  on  its  superior  aspect.  The  foramen  magnum  is  subcircular  in  outline, 
and  is  situated,  as  it  were,  in  the  middle  of  a  shallow  concavity. 

A  quadrate  has  an  extensive  anterior  surface  ;  transversely  elongated,  antero-pos- 
teriorly  compressed,  articular  facet  for  the  mandible  ;  a  double  mastoidal  head  ;  and 
a  broad,  squarely  truncated  orbital  process.  This  bone  is  also  pneumatic,  and  its 
articular  facet  for  a  pterygoid  is  rounded  and  projecting.  As  in  Sula,  there  is  a 
very  deep  pit,  of  no  mean  size,  immediately  in  front  of  the  mastoidal  process  of 
either  quadrate,  and  when  those  bones  are  in  situ,  they  arch  over  the  posterior  thirds 
of  these  pits,  in  such  a  manner  as  to  have,  in  each  case,  the  outer  mastoidal  head 
articulate  upon  the  outer  border  of  this  pit,  and  the  inner  head  upon  the  inner 
border.  Either  one  of  these  deep  excavations  is  situated  above  and  to  the  outer 


SHUFELDT:   OSTEOLOGY   OF  THE  STEGANOPODES 


121 


side  of  the  corresponding  osseous  opening  of  the  ear,  and  the  foramen  ovale.  Pos- 
teriorly the  cranial  surface,  in  so  far  as  the  occipital  area  is  concerned,  lies  in  the 
vertical  plane,  and  is  distinctly  reniform  in  outline,  bounded  all  about  by  a  raised 
osseous  ridge,  with  its  convex  curve  above,  and  the  foramen  magnum  situated  me- 
siad  in  the  concavity  below.  The  unpierced  supraoccipital  prominence  is  fairly 
well-developed,  and  occupies  the  mid-vertical  line  of  this  reniform  occipital  area, 
extending  from  the  foramen  to  the  limiting  curve  above. 

The  mandible  of  a  Tropic  Bird  is  somewhat  acutely  V-shaped  in  form  with  large 
and  deep  articular  cups  for  the  quadrates.  These  cups  have  large  pneumatic  foram- 
ina in  their  concavities,  with  a  single  such  opening  on  the  upper  side  of  their  short 
inturned  processes.  Behind,  they  are  vertically,  as  well  as  completely,  truncated. 


FIG.  2.     Superior  view  of  mandible  of  Pliacthon  xthereus. 
men  in  his  private  collection. 


Outline  sketch,  natural  size,  by  the  author  from  speci- 


Either  rarnal  moiety  is  very  deep,  and  laterally  compressed,  —  presenting,  well 
forward  of  the  articular  end,  a  large,  irregular  ramal  vacuity.  The  dentary  portions 
of  the  mandible  have  hardly  half  the  height  of  the  ramal  limbs  ;  they  are  thickened, 
and  each  is  deeply  grooved  for  nearly  the  entire  length  of  its  superior  margin. 
Anteriorly,  they  run  very  close  to  each  other,  and  the  terminal  symphysis  is  deep, 
averaging  in  depth  1.5  cm.  in  P.  xthereus,  being  nearly  2  cm.  in  some  specimens. 
In  an  eye  of  the  species  just  mentioned  I  count  some  15  osseous  sclerotal  plates  ;  they 
are  remarkable  for  the  extensive  manner  in  which  they  overlap  each  other,  and 
still  more  for  the  fact  that  the  anterior  ones  have  a  depth  of  not  more  than  one 
third  of  the  posterior  ones,  a  uniform  graduation  taking  place  in  the  intermediate 
plates,  above  and  below,  in  this  osseous  circlet. 

We  find,  too,  an  interesting  structure  in  the  bony  parts  of  the  hyoidmn  apparatus 
of  Phaethon.  In  the  adult,  the  ceratohyals  have  fused  in  ossification  with  the  posterior 
half  of  the  glossohyal  to  form  a  peg-like  bone,  which  is  longitudinally  grooved 
above  and  convex  below.  The  first  basibranchial  is  a  short,  thick  piece,  expanded 
in  front  to  form  an  articular  facet,  while  behind  it  supports  the  very  minute,  though 


122  MEMOIRS   OF   THE   CARNEOIK   MUSEUM 

free,  second  basibranchial.  Either  ceratobranchial  is  an  extremely  long,  slender  rod 
of  bone,  bearing  at  its  distal  end  a  little  bit  of  an  epibranchial,  which  latter  is  fin- 
ished off  posteriorly  by  a  thread-like  extension  in  cartilage.  Cartilage  also  tip  the 
glossohyal  in  sfront,  and  laterally,  the  ends  of  the  ceratohyals  may  not  entirely  ossify. 

For  the  trachea,  its  rings  seem  to  be  performed  in  elementary  osseous  tissue  only, 
and  in  mid-course  of  this  tube,  they  are  delicate  structures,  being  markedly  narrow 
in  depth,  and  very  frail. 

Of  the  Axial  Skeleton.  —  (See  Plate  XXL,  Figs.  5  and  6.)  Representatives  of  the 
genus  Phaethon  possess  in  the  cervical  and  cervico-dorsal  divisions  of  the  vertebral 
chain  15  bones.  Three  of  these  are  cervico-dorsals,  the  anterior  one  of  which 
always  supports  an  exceedingly  rudimentary  pair  of  free  riblets. 

In  P.  (ethereus  they  are  seen  to  be  in  the  same  condition  on  the  next  following 
vertebra,  or  the  14th  vertebra  of  the  neck,  while  in  P.  flavirostris  they  are  of  some 
considerable  length,  though  they  do  not  develop  epipleurse.  Both  species  have  a 
well-developed  pair  of  ribs  on  the  15th  segment  of  the  neck  vertebrae,  that  support 
epipleural  spines  on  their  posterior  margins,  to  which  part  they  are  firmly  coossified. 

The  atlas  is  comparatively  small  with  rather  slender  neurapophyses.  Its  cup  is 
profoundly  notched  above,  for  the  accommodation  of  the  odontoidal  process  of  the 
axis.  Below,  it  develops  a  low  hypapophysial  spine  projecting  backwards,  which, 
when  the  bones  are  articulated  in  situ,  underlaps  the  centrum  of  the  second  vertebra. 
A  prominent,  quadrate  hypapophysis  also  is  found  to  exist  beneatn  the  centra  of  the 
axis  and  third  vertebra,  but  this  feature  is  very  nearly  aborted  on  the  fourth  cervical. 

On  the  axis  vertebra  we  find  a  massive  neural  spine,  with  conspicuous  lateral  pro- 
jections, each  jutting  upwards  and  outwards  from  above  the  postzygapophyses.  All 
these  characters  are  moderately  reduced  in  the  third  vertebra,  while  in  the  fourth 
the  neurapophysis  is  very  much  reduced  in  size,  and  the  aforesaid  lateral  or  ana- 
pophysial  processes  are  all  but  absent. 

The  lateral  vertebral  canals  are  but  semi-closed  in  the  axis  ;  they  are  thoroughly 
so  throughout  the  rest  of  the  vertebral  chain  until  we  meet  with  the  leading  cervico- 
dorsal,  wherein  the  existence  of  a  pair  of  rudimentary  free  pleurapophyses  leaves 
these  canals  open. 

On  the  under  side  of  the  cervicals,  the  passage  for  the  carotid  canal  is  seen  to 
be  wide  open,  and  is  confined  to  the  5th,  6th,  7th  and  8th  vertebra?.  Throughout 
the  series,  beginning  with  the  third  cervical,  we  find  the  parial  backward  projecting 
spines  of  the  parapophyses  to  be  pointed,  and  exceedingly  stumpy  and  very  short. 

On  the  9th  a  median  hyapophysis  makes  its  appeai'ance,  which  is  larger  on  the 
10th,  more  quadrilateral  in  form  and  laterally  compressed  on  the  llth,  small  on  the 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  1 23 

12th,  and  still  more  so  on  the  cervico-dorsals,  where  there  coexists  with  it  the  barest 
suspicion  of  lateral  spines. 

Viewed  dorsad,  the  third  cervical  appears  to  have  a  quadrilateral  form,  which 
passes  to  the  more  oblong  shape  in  the  fourth,  and  the  bones  of  this  part  of  the 
column  commence  to  shorten  antero-posteriorly  with  sixth,  they  being  wider  than 
they  are  long  for  the  remainder  of  the  spinal  series.  The  last  two  cervico-dorsals 
develop  a  low,  quadrilateral  neural  spine,  which  resembles,  but  is  antero-posteriorly 
shorter  than  the  same  process  as  it  occurs  throughout  the  dorsal  vertebrae. 

P.  fiavirostris  has  a  delicate,  osseous,  interzygapophysial  bar,  extending  from  the 
back  of  either  prezygapophysis  backwards  and  inwards  to  the  corresponding  ante- 
rior bases  of  the  postzygapophyses,  in  the  fifth,  sixth  and  seventh  cervical  vertebrae. 
Usually  it  only  ossifies  in  the  fifth  and  sixth  in  P.  xthereus,  its  place  being  taken  by 
ligament  in  the  seventh  and  eighth.  No  such  character  as  this  is  ever  present  in 
any  of  the  Sididte.  Strong  and  broad  diapophysial  processes  are  first  pronounced 
in  the  first  and  second  cervico-dorsals ;  in  the  last  cervico-dorsal  these  processes  are 
markedly  shorter  and  shallower,  while  throughout  the  dorsal  series  of  vertebra}  they 
are  decidedly  slenderer,  and  in  their  vertical  diameters  of  very  little  thickness. 

Passing  to  the  dorsal  series  of  vertebrae,  we  find  in  P.flamrostris  six  of  those  bones 
freely  articulated  with  each  other  between  the  last  cervico-dorsal  and  the  leading 
one  in  the  consolidated  pelvic  sacrum.  This  last-mentioned  vertebra,  in  all  my 
specimens  of  P.  xtherem,  coossifies  with  the  anterior  sacral,  though,  as  we  shall  see 
presently,  this  difference  does  not  affect  either  the  number  or  the  arrangement  of 
the  thoracic  ribs.  Hypapophyses  are  fairly  well  developed  upon  all  the  dorsals  of 
the  middle  of  the  back,  but  they  become  small  as  we  near  the  pelvis,  to  be  very 
inconspicuous  or  entirely  absent  from  the  last  one  or  two  bones.  Pneumaticity 
characterizes  all  the  vertebrae  between  the  atlas  and  the  first  caudal,  and  the  centra 
of  the  dorsals  are  but  moderately  compressed  in  the  transverse  direction.  They 
present  the  usual  ornithic  plan  of  articulation  with  each  other,  and  the  same  may 
be  said  of  the  manner  in  which  the  true  ribs  are  connected  with  the  segments  of  this 
division  of  the  spinal  column.  There  are  five  pairs  of  these  ribs  that  bear  uncinate 
processes,  firmly  attached  to  the  middle  of  their  hinder  borders,  and  each  pair  of 
these  appendages  is  slender,  slightly  overlapping  the  succeeding  rib  in  every  case 
save  the  last,  which  may  or  may  not  be  of  sufficient  length  to  do  so.  As  for  the 
ribs  themselves,  they,  too,  are  long  and  narrow,  sweeping  well  backwards,  a  fact  that 
entails  the  presence  of  lengthy  hsemapophyses  to  reach  the  sternum.  These  latter 
are  of  no  great  caliber ;  the  first  pair  being  nearly  straight,  and  the  succeeding  pairs 
becoming  gradually  more  curved  as  we  approach  the  last  ones,  which  are  the  most 


124  MEMOIRS   OK   THE   CARNKGIE   MUSEUM 

so.  Finally,  there  are  two  pairs  of  thoracic  ribs  that  are  devoid  of  unciform  proc- 
esses, the  costal  ribs  of  the  first  of  which  reach  the  sternum,  but  those  of  the  ulti- 
jnate  pair  fail  to  do  so  by  some  considerable  distance  in  both  species.  From  what 
has  been  said  in  a  foregoing  paragraph,  it  will  be  seen  that  this  gives  one  true  pair 
of  "  pelvic  ribs,"  while  the  penultimate  pleurapophyses  and  their  hsemapophyses  in 
P.  flavirostris  articulate  with  a  vertebra  of  the  dorsum  which  is  free,  but  which  in  P. 
sethereiis  is  coossified  with  the  pelvic  sacrum.  So  were  we  to  have' studied  skeletons 
of  the  latter  species  only,  it  would  have  been  said  that  it  possessed  two  pairs  of 
"pelvic  ribs,"  and  had  P.  flavirostris  alone  been  examined  in  this  particular,  the 
descriptive  osteologist  would  have  recorded  but  one  pair.  This  is  but  another 
instance  exemplifying  the  great  necessity  of  having  the  proper  material  in  sufficient 
variety  before  one  for  comparison. 

Viewing  the  pelvis  from  above,  we  find  that  the  anterior  margins  of  the  ilia  over- 
lap the  penultimate  pair  of  thoraric  ribs  in  the  Red-billed  Tropic  Bird,  not  so,  how- 
ever, P.  flavirostris;  and  this,  taken  in  connection  with  the  apparent  appropriation 
on  the  part  of  the  sacrum  of  one  of  the  dorsal  vertebrae,  already  referred  to  above, 
in  the  case  of  the  first-named  species,  lends  to  the  pelvis  a  difference  of  appearance 
in  the  skeletons  of  the  two  birds,  now  under  consideration,  which  is  not  otherwise 
particularly  borne  out  by  this  bone.  In  part,  the  pelves  of  these  specimens  are  other- 
wise very  much  alike.  Disregarding,  then,  the  vertebra  to  which  reference  has  just 
been  made,  we  find  the  sacrum  to  be  composed  of  ten  others,  which  are  thoroughly 
fused  together  and  with  the  ilia,  one  upon  either  side.  Taken  as  a  whole,  the  pelvis 
is  broad,  not  especially  long,  and  very  shallow  and  compressed  in  the  vertical  direc- 
tion. The  internal  borders  of  the  ilia  are  nearly  parallel  to  each  other,  and  the 
broad  sacrum  keeps  them  well  apart  for  their  entire  length.  Such  an  arrangement, 
as  we  might  expect,  gives  open,  shallow  "  ilio-neural  grooves,"  one  on  either  side 
of  the  sacral  crista,  anteriorly.  These  are  quite  continuous  with  similar  "  groov- 
ings"  carried  back  posteriorly  as  far  as  the  first  caudal  vertebra.  In  other  words, 
between  the  inner  borders  of  either  ilium,  and  the  supero-median  line  of  the  sacrum, 
the  diapophyses  of  the  vertebra?  are  found  to  be  below  the  general  surface ;  while 
between  them,  for  the  entire  length  of  the  pelvis,  occur  foramina  of  some  size,  and 
more  or  less  subcircular  in  outline.  These  single  parial  rows  of  interdiapophysial 
foramina  constitute  a  striking  character  upon  the  superior  aspect  of  the  pelvis  of 
the  Tropic  Birds,  inasmuch  as  in  the  preacetabular  portion  of  that  bone  in  Sula, 
Plotix,  the  Pelicans,  and  the  Cormorants,  they  are  out  of  sight  on  this  aspect  by  the 
internal  margins  of  the  ilia  meeting  the  sacral  crista.  Thus  it  will  be  appreciated 
that  the  breadth  of  the  pelvis  in  Pliaetkon,  to  which  allusion  has  been  made,  is 


SHUFELDT  :     OSTEOLOGY    OF   THE    STEGANOPODES  125 

chiefly  due  to  the  broad  sacrum,  and  not  to  the  ilia,  which  bones,  either  in  their 
pre-  or  postacetabular  parts,  are  quite  narrow  in  their  transverse  direction.  The 
former  area,  in  each  one,  being  very  slightly  concaved,  and  in  the  latter,  barely 
convexed.  Antitrochanterian  processes  are  comparatively  prominent,  and  each 
overhangs  a  cotyloid  cavity  of  moderate  size,  and  of  the  usual  ornithic  character. 
Laterally  viewed,  we  note  that  the  obturator  foramen  is  complete,  due  to  the  fact 
that  either  pubic  style  is  in  contact  for  nearly  its  entire  length  with  the  inferior 
margin  of  the  corresponding  ischium.  This  obliterates  anything  like  an  obturator 
space.  Each  pubic  style  is  long  and  somewhat  slender,  and  often  passing  an  ischium 
behind,  curves  downwards  and  very  slightly  inwards.  Here  the  bone  is  appreciably 
dilated  in  P.  fethereus,  which  is  not  the  case  in  the  other  species  we  are  considering. 
An  ischium  is  also  narrow,  and  projects  some  distance  beyond  the  ilium  of  the  same 
side.  A  very  shallow  ilio-ischiac  notch,  on  the  posterior  pelvic  border,  is  formed 
by  this  arrangement ;  but  by  no  means  as  well  marked  an  one  as  we  see  in  the 
more  typical  steganopods,  to  be  described  later  on  in  this  memoir. 

The  ilio-ischiac  foramen  is  large  and  of  a  subelliptical  outline  (see  Fig.  6,  PL  XXL). 
On  the  under  side  of  the  pelvis  in  Phaethon,  we  are  to  note  the  fact  that  the  sacral  ver- 
tebrse,  opposite  the  acetabula,  do  not  throw  out  their  processes  to  act  as  braces  to 
especially  strengthen  the  ilio-pelvic  walls  at  those  points,  a  feature  often  seen  in  the 
skeletons  of  other  birds,  and,  as  before  found,  both  by  Mivart  and  myself,  to  be  the 
case  in  Pelacanus,  the  true  cormorants,  in  Sula,  and  to  a  somewhat  less  conspicuous 
degree  in  Anhinga. 

Eight  free  caudal  vertebra,  plus  an  elongated,  ploughshare-shaped  pygostyle,  go  to 
make  up  the  skeleton  of  the  tail  in  a  Tropic  Bird.  These  vertebrae  have  spreading 
diapophyses,  especially  the  fifth  one,  and  all  have  neural  spines,  while  the  last  three 
of  them  possess  bifid  haemal  spines;  and  this  last  character  is  impressed  upon  the 
lower  end  of  the  coccyx.  The  neural  canal  passes  through  the  entire  series.  From 
this,  and  including  the  coccygeal  piece,  it  will  be  seen,  from  our  account  of  the  spinal 
column,  as  it  has  been  given  above,  to  contain  in  these  birds,  forty  vertebrae.  They  are 
all  pneumatic,  except  the  atlas  and  those  which  go  to  form  the  skeleton  of  the  tail. 

The  Sternum.  —  This  bone  in  my  specimen  of  Phaethon  flavirostris  has  a  body  of  a 
quadrilateral  form,  being  almost  as  wide  as  it  is  long.  Its  carina  is  deep  anteriorly, 
where  it  protrudes  far  forwards,  while  behind  it  merges  with  the  ventral  surface  of 
the  body  at  some  distance  before  it  reaches  the  mid-xiphoidal  process.  In  front  the 
carinal  angle  is  thickened,  and  upon  its  superior  aspect  there  exists  a  considerable 
facet  for  articulation  with  infero-median  surface  of  the  osfurcula.  This  facet  is  not 
at  the  apex,  but  is  found  about  one  third  the  distance  back  towards  the  sternal  body, 


126  MEMOIRS    OF    THE    CARNEGIE    MUSEUM 

and  the  articulation,  though  very  close  and  extensive,  is  free,  and  anchylosis  has  never 
been  seen  by  me  to  take  place  between  the  two  bones.  The  coracoidal  grooves  decussate, 
the  median  extremity  of  the  right  one  passing  beneath  the  median  extremity  of  the  left. 
A  very  rudimentary  manubrium  is  seen  immediately  below  this  point,  and  below  it  a 
circular  pneumatic  foramen.  Either  costal  process  is  broad  and  subtriangular  in  form, 
and  upon  either  costal  border  occur  six  facets  for  articulation  with  the  hsemapoph- 
yses  which  connect  the  sternum  with  the  vertebral  ribs.  On  the  much-concaved 
sternal  body,  just  within  the  anterior  border  in  the  median  line,  dorsad,  there  runs 
back  longitudinally  a  characteristic  bridge  of  bone,  upon  either  side  of  which  we 
find  a  large  subelliptical  pneumatic  foramen,  and  usually  they  are  the  only  two 
found  in  this  situation.  Other  small  ones  occur,  however,  in  the  pitlets  among  the 
hsemapophysial  facets  on  the  costal  borders.  Very  broad  external  xiphoidal  proc- 
esses of  the  posterior  part  of  the  sternal  body,  extend  further  backwards  than  any 
other  part  of  the  bone ;  the  middle  xiphoidal  process  is  broadly  rounded.  The  in- 
ternal pair  of  processes  are  small  and  delicate,  and  each  one  of  the  pair  occupies  a 
mid-point  in  the  great,  round  notch,  on  either  side,  existing  between  the  mid-  and 
external  xiphoidal  process,  thus  creating  a  4-notched  sternum  for  this  species,  of  a 
peculiar  pattern  in  this  respect.  Mivart  has  said  in  his  "Axial  Skeleton  of  the 
Pelecanidfe"  (T.  Z.  S.,  p.  365),  that  "in  the  Pelecanidx  there  is  but  a  single  lateral 
xiphoid  process  on  each  side,  while  in  Phaethon  there  are  two  on  each  side,  in  addi- 
tion to  the  median  xiphoid  process."  Farther  on  we  shall  see  that  this  by  no  means 
always  holds  good  for  P.  tethereus.  Passing  next  to  the  consideration  of  the  sternum 
in  the  species  last  mentioned,  we  observe  that  in  the  majority  of  its  characters  it 
agrees  with  the  bone  as  it  has  just  been  described  for  P.  flavirostris.  It  is  propor- 
tionately larger  however,  and  presents  two  striking  differences.  In  the  first  place, 
in  all  four  of  my  specimens  a  large,  blunt-pointed  manubrium  is  present,  which  is 
transversely  pierced  at  its  base  b}^  a  foramen.  Again,  the  internal  pair  of  xiphoidal 
processes  may  be  entirely  absent,  or  only  one  may  be  present  on  one  side,  and  when 
such  is  the  case,  it  appears  only  as  a  minute  projection  from  the  inner  border  of  the 
external  xiphoidal  process  near  its  extremity.  I  have  no  specimens  of  the  sternum 
of  P.  sethereus  wherein  there  is  to  be  found  a  pair  of  internal  xiphoidal  processes, 
and  consequently  its  sternum  is  not  four-notched  as  in  its  cogener,  P.  flavirostris. 
More  or  less  minute  or  scattered  pneumatic  foramina  may  be  found  on  its  thoracic 
surface,  above  the  two  large  ones  which  occupy  similar  positions  to  those  noticed  in 
the  Yellow-billed  Tropic  Bird. 

The  os  furcula  is  of  the  broad  U-shaped  pattern,  with  its  median  portion  below, 
widened,  and  on  the  under  surface  of  which  occurs  the  facet  for  articulation  with  the 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPOIJES 


127 


keel  of  the  sternum  as  described  above.  The  upper  free  extremities  of  the  clavicles  are 
drawn  out,  rounded,  blunt-pointed  and  the  apex  of  each  one,  when  articulated  in  situ, 
reaches  back,  on  either  side,  to  the  antero-mesial  angle  of  the  corresponding  scapula. 

A? scapula  is  long,  very  narrow,  rounded,  and  somewhat  compressed  in  the  ver- 
tical direction.  Its  distal  end  only  is  blade-like,  very  slightly  expanded,  and 
obliquely  truncated  from  a  point  within  to  the  apex.  It  articulates  in  the  usual  or- 
nithic manner  with  the  coracoid,  and  neither  it  nor  the  os  furcula  appear  to  be  pneu- 
matic, as  is  the  coracoid.  This  latter  bone  of  the  shoulder-girdle  has  a  broad,  much 
expanded  sternal  extremity,  which  supports  a  moderately  prominent  lateral  coracoid 
process.  The  entire  length  of  the  bone  is  greater  than  half  the  length  of  the  humerus, 
and  its  shaft  is  compressed  in  the  oblique  antero-posterior  direction.  Its  head  or 
summit  is  tuberous,  and  also  somewhat  compressed  in  the  same  plane  with  the 
shaft.  The  process  for  articulation  with  the  os  furcula  is  large,  much  flattened  from 
side  to  side,  and  low  down  in  the  deep  tendinal  groove  it  creates,  we  observe  a 
minute  antero-posterior  perforation  of  the  bone.  As  usual,  the  coracoid  and  scapula 
form  a  well  defined  glenoid  cavity  for  articulation  with  the  head  of  the  humerus.  An 
os  humero-scapulare  is  not  found. 

Of  the  Appendicular  Skeleton.  The  Pectoral  Limb :  Apart  from  the  mere  matter 
of  the  difference  in  size,  the  bones  composing  the  limbs  in  the  skeletons  of  these  two 
species  of  Phaethon  are  in  their  corresponding  characters  .almost  exactly  alike,  and 
these  again  are  notably  different  from  those  same  characters  as  we  find  them  exem- 
plified in  the  limb-bones  of  the  skeletons  in  other  families  of  the  Steganopodes. 
These  departures  will  be  noted  from  time  to  time  later  on  in  this  paper,  after  the 
present  account  of  the  osteology  of  the  Tropic  Birds  has  been  written. 

In  the  brief  subjoined  table  some  of  the  lengths  of  the  bones  are  compared,  the 
measurements  being  given  in  centimeters  and  fractions. 


TABLE. 


Measurements,  taken  from  extreme  distal  points, 

Species. 

and  not  on  curved  contour  lines. 
P.  flavirostna. 

/'.  mthereas. 

Length  of  humerus.                                                                    8.4 

9.3 

Length  of  ulna.                                                                               8.9 

9.7 

Length  of  carpo-metacarpus.                                                    4.3 

4.8 

Length  of  proximal  phalanx  of  index  digit. 

2.5 

2.9 

Length  of  distal  phalanx  of  index  digit.                                    2.4 

2.8 

Total  length  of  pinion  (articulated).                                           8.8 

10.1 

Length  of  femur.                                                                             3.2 

3.7 

Length  of  tibio-tarsus. 

4.7 

5.3 

Length  of  tarso-metatarsus. 

23 

2.8 

Length  of  mid  anterior  toe. 

.8.8 

4.2 

128  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

From  this  it  will  be  seen  that  both  the  proportionate  and  relative  lengths  of  cer- 
tain long  bones  of  the  limbs  in  these  two  species  of  birds  slightly  differ,  but  the  dif- 
ference is  very  slight. 

There  is  no  especial  association  of  characters  in  either  the  pectoral  or  pelvic 
limbs  of  Phaethon  that  in  any  way  remind  us  of  the  corresponding  parts  of  the  skel- 
eton in  a  Gull,  or  a  Tern,  much  less  any  kind  of  an  Auk  or  a  Puffin.  The  several 
bones  seem  to  possess  a  distinctive  character  quite  their  own.  The  humerus  shows 
a  slight  compression  in  the  transverse  direction,  rendering  its  humeral  head  narrow, 
and  its  very  moderately  curved  shaft  ellipsoidal  rather  than  circular  on  section. 
The  well-marked  ulnar  tuberosity  projects  directly  anconad,  as  does  the  prominent 
radial  crest  project  palmad, — the  long  transverse  axis  of  the  first  being  parallel  to 
the  plane  of  the  latter.  At  the  proximal  end  of  the  bone,  on  its  palmar  aspect,  just 
before  we  come  to  the  humeral  head,  we  meet  with  a  well-defined  groove  running 
at  right  angles  to  the  long  axis  of  the  shaft ;  and  this  groove  becomes  very  deeply 
marked  at  a  point  on  the  opposite  side  of  the  bone  from  the  ulnar  tuberosity. 

The  "pneumatic  fossa"  instead  of  being  entirely  open,  as  in  a  good  many  birds, 
is  covered  across  by  a  more  or  less  perfect  bony  plate,  which  plate  shows  the  single,  cir- 
cular pneumatic  perforation  at  its  center.  This  hole  is  smaller  in  proportion  in  my 
specimen  of  P.  flavirostris  than  it  is  in  the  other  species.  At  the  distal  end  of  the 
bone  the  fossa  above  the  oblique  and  ulnar  tubercles  is  fairly  well  scooped  out ; 
while  on  the  ulnar  side  of  the  humerus  at  this  end,  both  the  pits  for  tendinal  inser- 
tion and  the  grooves  for  their  passage  are  unusually  well  marked  and  deep.  An 
exceedingly  rudimentary  "  epicondyloid  process  "  can  be  seen,  but  it  by  no  means  is 
the  characteristic  feature  that  we  find  it  to  be  in  the  humeri  of  the  Laridx,  and 
those  suborders  of  birds  most  nearly  related  to  them. 

The  radius  is  straight  and  of  a  more  or  less  uniform  caliber,  while  its  companion 
bone  of  the  antibrachium,  the  ulna,  is  considerably  bowed,  with  its  shaft  presenting 
three  faces  more  or  less  distinctly.  These  might  be  here  designated  as  a  palmar  face 
or  surface,  an  interosseous  face,  and  a  subanconal  face.  The  line  or  angle  formed  by 
the  intersection  of  the  subanconal  and  palmar  faces,  has  along  it  the  row  of  papillae 
of  the  secondary  quill-feathers ;  and  another  indistinct  row  of  them  passes  down 
the  middle  of  the  subanconal  surface.  There  are  fourteen  such  papillae  in  the  first 
mentioned  row.  The  olecranon  process  is  a  very  insignificant  affair,  while  at  the 
distal  extremity  of  the  bone,  at  its  anconal  side,  the  end  is  drawn  out  into  a  dis- 
tinct apophysis,  which,  in  articulation,  bends  down  towards  the  ulnare  ossicle  of  the 
wrist.  Two  segments  compose  the  skeleton  of  the  carpus  in  the  adult,  the  usual 
radiale  and  the  just-mentioned  ulnare. 


SHUFELDT  :     OSTEOLOGY   OF   THE   STEGANOPODES  1 29 

Carpo-metacarpus  presents  us  for  examination  the  ornithic  characters  common  to 
many  representives  of  this  class  of  vertebrates.  The  coossified  pollex  metacarpal 
is  of  average  size,  and  the  slender  shaft  of  the  medius  metacarpal  is,  for  the  greater 
part  of  its  continuity,  parallel  with  the  far  heavier  shaft  of  index.  This  last,  at  the 
anterior  aspect  of  its  distal  end,  develops  a  pronounced  little  process,  which  serves 
to  retain  in  their  proper  groove,  the  tendons  which  pass  in  that  region  during  the 
life  of  the  individual.  The  free  digit  of  pollex  has  the  usual  form  seen  in  Aves 
generally,  and  the  expanded  posterior  portion  of  the  proximal  phalanx  of  the  index 
finger  is  entire,  and  not  perforated  as  we  find  it  in  many  of  the  Laridie.  The  distal 
joint  of  this  digit  is  long  and  slender,  being  once  semibarbed  near  its  lip,  the  pro- 
jection standing  out  from  its  posterior  angle.  Long  and  spine-like,  the  free  joint  of 
medius  is  seen  to  be  proportionately  more  slender  in  the  Red-billed  than  it  is  in  the 
Yellow-billed  Tropic  Bird.  There  do  not  appear  to  be  any  free  terminal  ungual 
joints  at  the  ends  of  any  of  the  fingers  in  these  birds ;  and  I  have  found  no  small 
sesamoidal  bones  either  about  the  carpus  or  near  the  elbow  joint. 

The  humerus  alone  of  the  bones  of  the  pectoral  limb  is  pneumatic. 

Passing  to  the  consideration  of  the  pelvic  limb,  we  find  that  the  femur  too,  is  gener- 
ally a  pneumatic  bone,  and  is  peculiar  inasmuch  at  the  foramina  occur  irregularly  at 
the  proximal  end  of  the  shaft  either  in  front  or  behind,  while  in  P.  asthereus  a  single, 
circular  pneumatic  foramen  is  found  in  the  majority  of  skeletons  in  the  popliteal  fossa 
near  its  center.  For  its  proximal  moiety,  tibio-tarsus  may  likewise  be  hollow,  and, 
in  life,  air  gains  access  to  its  interior.  In  one  of  my  specimens  a  small  perforating 
foramen  is  seen  between  the  low  cnenial  crests  very  near  the  summit  of  the  bone. 
Below  the  point  indicated,  the  remainder  of  the  skeleton  of  the  pelvic  limb  seems 
to  be  non-pneumatic. 

The  axis  of  the  head  of  the  femur  makes  a  wide  obtuse  angle  with  the  longitu- 
dinal axis  of  the  shaft,  and  the  pit  for  the  insertion  of  the  ligamentum  teres  is  but 
very  faintly  marked  upon  the  top  of  it.  On  the  summit  of  the  bone  we  find  the 
usual  articular  surface,  and  above  this  the  trochanterian  crest  is  scarcely  at  all  ele- 
vated. At  the  proximal  end  of  the  shaft,  between  the  great  trochanter  and  the  caput 
femoris,  a  very  appreciable  fossa  exists,  and  immediately  below  this  a  very  distinct 
tubercle  presents  itself  in  a  great  many  specimens  especially  of  Pha'ethon  asthereus.  It 
at  once  reminds  one  of  the  trochanter  minor  of  the  mammalia,  and  no  such  a  char- 
acter is  ever  to  be  seen  upon  the  femora  of  any  of  the  other  steganopodous  birds 
judging  from  those  before  me,  and  I  do  not  now  recall  ever  having  seen  it  upon  the 
femur  of  any  other  existing  or  extinct  bird.  This  character  is  but  faintly  seen  in 
the  U.  S.  National  Museum  specimen  of  the  skeleton  of  P.  ftavirostris  (No.  17841). 


130  MEMOIRS   OF    THE   CARNEGIE   MUSKUM 

At  the  distal  end  of  the  femur  the  condyles  are  not  very  prominent,  and  the  inter- 
nal one  is  small.  Nor  is  the  rotular  channel  or  the  popliteal  fossa  deep,  b\it  on  the 
contrary  they  are  both  shallower  than  in  many  other  birds  known  to  me.  We  find 
the  shaft  in  tibio-tarsus  to  be  straight  and  nearly  cylindrical.  Proximally,  the  low 
cnemial  process  rises  but  a  little  above  the  summit  of  the  shaft,  while  anteriorly, 
below  it,  the  pro-  and  ectocnemial  ridges  are  but  very  inconspicuously  developed. 
It  is  between  these  latter  that  the  small  pneumatic  foramen  usually  is  seen.  Distally 
the  usual  characters  of  this  bone  are  to  be  observed  ;  the  osseous  span  to  confine  tendons, 
at  the  antero-distal  end  of  the  shaft  is  present,  and  passes  in  a  slightly  oblique  direc- 
tion over  the  channel  it  bridges ;  the  condyles,  with  their  usual  reniform  contour,  are 
well  separated  from  each  other,  and  the  intercondyloid  notch  between  them,  is 
marked  in  front,  but  very  shallow  behind.  In  the  fibula  we  see  a  very  slender  and 
rudimentary  bone.  Especially  is  this  the  case  below  the  'fibular  ridge'  on  the  side 
of  the  shaft  of  the  bone  it  articulates  with,  for  it  is  then  reduced  to  little  more  than 
a  flattened  osseous  hair,  closely  applied  to  tibio-tarsus,  but  apparently  never  actually 
anchyloses  with  it. 

Phaethonidse  always  possess  a  patella  in  front  of  the  knee-joint,  and  it  is  of  an 
elongated  form,  being  flat  behind  and  convex  in  front,  where  it  is  distinctly  marked 
in  the  transverse  direction  by  the  groove  for  the  tendon  of  the  ambiens  muscle. 

Most  remarkable  of  all  the  bones  of  the  pelvic  limb  in  Phaethon,  however,  is  its 
tarso-metatarsm.  To  describe  this  I  select  the  left  one  from  one  of  my  skeletons  of 
P.  tfthereus.  The  bone  is  oblong  in  outline;  much  flattened  in  the  antero-posterior 
direction ;  and  with  its  middle  trochlear  process  but  slightly  lower  on  the  shaft 
than  the  internal  one,  which  latter  in  turn  is  but  a  little  lower  than  the  outermost 
one.  On  the  summit,  the  shallow  articular  depressions  for  the  condyles  of  the  tibio- 
tarsus  are  separated  by  a  rounded  eminence  in  front.  At  the  back  of  the  shaft,  in 
this  region,  we  find  the  "  hypotarsus"  to  consist  simply  of  three  vertical  ridges, — 
a  short,  small  middle  one,  with  longer  and  stouter  outer  ones.  Anteriorly,  the  shaft 
of  the  bone  is  deeply  scooped  out  from  above,  downwards  for  nearly  its  entire 
length.  On  the  outer  side  below,  this  channel  terminates  in  an  antero-posterior 
perforating  foramen, —  situated  at  a  point  a  little  above  the  notch  dividing  the 
mid-  and  outer  trochlear  processes.  On  the  inner  side  below,  there  is  a  small,  longi- 
tudinally-disposed groove  that  runs  into  the  main  excavation  on  this  aspect  of  the 
shaft  at  about  its  middle.  This  smaller  groove  also  terminates  below  in  an  antero- 
posterior  perforating  foramen, —  situated  at  a  point  a  little  above  the  notch  divid- 
ing the  mid-  and  inner  trochlear  processes.  Thus  we  see  in  P.  xthcreus,  there  are 
two  antero-posterior  perforating  foramina  at  the  distal  extremity  of  its  tarso-meta- 


SHUFELDT  :     OSTEOLOGY    OF   THE    STEGANOPODES 


131 


tarsus;  — a  very  rare  condition  in  existing  birds,  and  even  absent  in  P.  flavirostris, 
where  only  the  usual  outer  foramen  seems  to  be  present. 

At  the  back  of  the  shaft  there  is  a  low  median  ridge  running  down  from  the 
lowermost  point  of  the  hypotarsus  to  bifurcate  below.  One  limb  is  lost  on  the  pos- 
terior surface  of  the  mid-trochlear  process,  the  other  on  the  outer  one,  while  between 
them  occurs  the  outer  of  the  two  perforating  foramina  just  described  above.  Upon 
either  side  of  this  ridge,  the  shaft  upon  this  aspect  is  also  grooved  in  the  longi- 
tudinal direction,  but  not  so  deeply  as  it  is  in  front.  Placed  side  by  side  in  the 
anterior  groove  of  the  bone,  just  below  the  head,  we  find  a  pair  of  perforating  foram- 
ina. They  make  their  exit  one  upon  either  side  of  the  lower  part  of  the  hypo- 
tarsus  behind ;  each  one  lying  in  a  postero-longitudinal  groove,  to  which  mention 
has  just  been  made  in  the  last  paragraph.  The  sides  of  the  shaft  of  this  bone  of  the 
leg  are  more  or  less  flattened,  and  the  tubercle  for  the  insertion  of  the  tibialis  anticus, 
is  very  small.  The  first  metatarsal  is  free,  being  long  and  flake-like,  and  articulates 
by  its  entire  outer  margin,  with  the  postero-internal  edge  of  the  shaft  of  the  tarso- 
metatarsus.  Pes  has  what  is  usually  termed  the  normal  arrangement  and  number 
of  joints  to  the  several  toes,  i.  e.,  2,  3,  4  and  5  joints,  to  the  hallux,  second,  third  and 
fourth  digits  respectively.  Exceedingly  slender  and  long,  the  basal  joint  of  hallux 
is  tipped  off  with  a  small,  slightly  curved  ungual  phalanx.  The  terminal  pha- 
langes of  the  three  anterior  toes  are  relatively  much  stouter,  thicker,  but  exhibit 
about  the  same  proportionate  amount  of  curvature.  With  respect  to  the  shafts  of 
the  intermediate  joints,  it  is  to  be  noted  that  they  are  long,  slender,  and  exhibit  but 
very  little  curving;  while  the  articular  ends  of  these  bones  are  but  very  slightly 
enlarged.  Indeed,  the  skeleton  of  the  foot  in  the  Phaethonidss  is  in  reality  deli- 
cately constructed. 

TABLE. 


Toes  and  their  joints. 

P.  flnvirostris. 
Measurements  in  mm. 

Remarks. 

Hallux  or  First  Toe. 
Second  or  Inner  Toe. 

Third  or  Middle  Toe. 
Fourth  or  Outer  Toe. 

|  Basal  jo 
(  Ungual 
I  Basal 
<  Second 
(  Ungual 
f  Basal 

]  Third 
[  Ungual 
f  Basal 
Second 
\  Third 
Fourth 
[  Ungual 

nt  

11 

4 
15 
12 
5 
12 
11 
10 
5.1 
10 
8 
8 
8.5 
4 

} 

1 

) 

From  this  it  will  be  seen  that 
the  length  of  the  skeleton  of 
the  middle  toe  is  about  *  the 
length  of  the  tibio-tarsus.  On 
the  other  hand  it  is  longer  than 
either  the  femur  or  the  tarso- 
meta  tarsus. 



132  MEMOIRS   OP   THE   CARNEGIE    MUSEUM 

A  proportionate  increase  in  their  length  and  caliber  seems  to  be  the  only  im- 
portant difference  that  distinguishes  the  skeletal  toe-joints  of  P.  sethereus  from  the 
corresponding  bones  in  P.  flavirostris.  To  show  the  relative  lengths  of  the  pha- 
langes in  the  last  named  species,  see  the  above  table,  in  which  the  measurements 
are  given  in  millimeters. 

Beyond  the  patella,  already  described  above,  I  find  no  other  sesamoids  associated 
with  the  bones  of  the  pelvic  limb  in  the  Phaethontidas. 


OSTEOLOGY  OF  THE 

(See  Plates  XXII.  and  XXIII.,  Figs.  7-12.) 

Of  the  Skull.  —  Sula  bassaua  has  a  skull  that  averages  in  the  adult  about  186  mm. 
in  length  ;  whereas  in  Sula  piscator  129  mm.  is  the  average  length  of  the  skull  in 
the  adult.  Between  these  extremes  we  find  the  other  species  to  fall,  and  a  simliar 
variation  is  size  is,  of  course,  applicable  to  the  remainder  of  the  skeleton  in  these 
different  specific  forms  of  the  Sulidae.  Apart  from  this,  the  characters  presented  in 
the  skeletons  of  these  birds  in  the  main  agree  very  well  indeed,  though  differences 
do  exist,  and  these  stamp  the  skeleton  of  each  species  with  an  individuality  peculiarly 
its  own.  The  more  important  of  these  differences  will  be  noted  as  we  proceed. 
(See  Plates  XXII.,  XXIII.,  Figs.  7-11.) 

In  form,  the  superior  osseous  mandible  is  flat  upon  its  under  side  with  cultrate 
tomia,  while  superiorly  it  is  convex  from  side  to  side,  and  tapers  from  base  to  apex 
gradually  to  a  point,  being  a  little  decurved  near  the  extremity.  Sometimes  we 
find  it  pierced  by  a  foramen  on  this  upper  side,  which  leads  to  its  hollow  interior, 
but  Sula  is  without  nostrils,  though  did  they  exist,  their  position  would  perhaps  be 
indicated  by  the  posterior  end  of  the  longitudinal  furrow  that  marks  the  mandible 
upon  its  lateral  aspect.9 

An  osseous,  thoroughly  adherent  crust,  appears  to  overlay  the  greater  part  of  the 
superior  surface,  the  only  smooth  place  being  a  small  area  in  front  of  the  cranio- 
facial  hinge,  and  even  this  is  absent  in  Sula  piscator  and  other  species.  Its  entire 
surface  is  marked  all  over  by  an  exquisite  anastomosing  venation,  the  ramifications 

8  Besides  some  four  fossil  forms,  Dr.  R.  Bowdler  Sharpe  in  his  recent  Hand  List  of  Birds,  recognizes  the  following 
species  of  the  genus  Sula,  in  which  are  included  all  the  birds  of  this  group  at  present  known  to  ornithologists  :  —  viz  : 
S.  basxana,  S.  serrator,  8.  capenxin,  S.  cyanops,  S.  abnoti,  S.  piscatrix,  S.  webuleri,  S.  variegata.  S.  nebouxi,   S.  sula  and  S. 
brewsleri.     In  the  A.  O.  U.  ''Check-List"  we  also  finds,  gossi,  which   may  correspond   with  one  of  the  species  above 
enumerated,  as  S.  nebouxi,  or  S.  websteri. 

9  In  my  memoir  entitled   "  Observations  upon  the  Osteology  of  the  Orders  Tubinares  and  Steganopodes  (Proc.  U. 
S.  Nat.  Mus.  Vol.,  XL,  1888,  pp.  253-315),  I  give  figures  of  all  the  principal  bones  of  the  skeleton  of  Sula  bassana,  drawn 
by  me,  natural  size,  direct  from  the  specimens.     These  will  not  be  reproduced  here,  while  the  osteology  of  other  species 
of  Gannets  will  be  illustrated  in  the  plates  of  the  present  memoir,  as  S.  gossi  and  S.  brewsteri. 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  133 

starting,  in  some  instances,  from  minute  foramina  found  upon  its  surface.     This 
venation  is  but  feebly  marked  in  S.  piscator. 

A  lacrymal  is  a  free  bone,  articulating  with  a  roughened  facet  of  some  extent  be- 
neath the  antero  external  angle  of  the  frontal  above,  and  by  a  smooth,  gliding  facet 
on  the  upper  side  of  the  maxillary,  which  latter  bone  is  thickened  in  a  perpendic- 
ular direction  and  otherwise  enlarged  in  order  to  offer  it  the  proper  amount  of  sur- 
face. As  for  the  bone  itself,  it  is  of  rather  a  columnar  form,  with  the  exception  of 
its  extended  anterior  margin,  which  is  roundly  notched  and  shows  on  its  inner  side 
the  large  pneumatic  opening  leading  to  its  hollow  interior.  In  S.  cyanops  this  notch 
is  extended  as  a  groove  entirely  across  the  outer  face  of  the  bone,  and  the  pneu- 
matic foramen  is  seen  in  this  groove. 

In  Gannets  there  exists,  projecting  horizontally  from  the  outer  margin  of  the 
frontal  bone,  on  either  side,  from  its  "  prefrontal  process,"  a  few  millimeters  posterior 
to  the  fronto-lacryraal  suture,  a  small  rounded  ledge  of  membrano-cartilage,  which 
reminds  one  of  the  horizontal  portion  of  the  true  lacrymal  bone  in  certain  gallina- 
ceous birds,  as  the  Perdicinse,  for  example.  This  feature  has  been  studied  by  me  in 
Sula  brewsteri  and  S.  gossi,  recently  killed  specimens  for  which  I  am  indebted  to 
Mr.  E.  J.  Reed  of  Guaymas,  Mexico,  who  kindly  collected  them  for  me.  This 
membrano-cartilaginous  process  probably  never  ossifies  in  the  Sulidse. 

In  the  adult  bird  it  is  impossible  to  distinguish  the  exact  position,  or  any  of  the 
borders,  of  the  nasal  bone. 

The  maxillo-jugal  bar  shows  very  plainly  the  suture  between  the  jugal  and 
quadrato-jugal ;  the  latter  is  much  smaller  than  the  other  portion,  and  shows  a 
strong  peg-like  process  upon  the  inner  aspect  of  its  posterior  end,  which  is  about  at 
right  angles  to  the  axis  of  the  bone.  It  fits  in  the  deep  conical  socket  on  the  side 
of  the  quadrate.  Beyond  its  enlargement  for  the  lacrymal  the  maxillary  is  a  thin, 
horizontal  plate  of  bone,  anchylosed  in  the  usual  way  at  its  anterior  end.  Here  it 
really  enters  into  the  apparatus  of  the  cranio-facial  hinge.  An  ossicle  having  the 
appearance  of  a  process  pointing  backward  and  apparently  coming  from  the  pre- 
maxillary  is  seen  over  this  horizontal  plate  of  the  maxillary  on  either  side.  Pro- 
fessor Parker  found  this  condition  present  also  in  another  species  of  Sula,  and  this 
eminent  anatomist  apparently  describes  this  ossicle  as  a  "post-maxillary"  for  those 
birds.  Either  rudimentary  or  better  developed,  it  is  probably  present  in  one  form 
or  another  in  all  of  the  SulidiS. 

The  interorbital  septum,  which  is  a  thin,  smooth  plate,  shows  considerable  of  a 
fenestra  near  its  middle,  and  a  few  such  openings  of  a  very  much  smaller  size  pierce 
its  posterior  wall  in  S.  bassana. 


134  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

The  orbital  cavity  itself  in  Gannets  is  very  deep,  the  eaves  of  its  roof  almost 
overhanging  the  jugal  bar  beneath.  Its  superior  periphery  is  smooth  and  rounded. 
All  in  front  of  the  rhinal  chamber  is  filled  in  by  the  spongy  mass  formed  by  the 
united  maxillo-palatines.  The  hinder  portions  of  these  bones  are,  however,  still  dis- 
tinct in  S.  bassami,  and  they  have  all  the  appearance  of  these  elements  as  they  are 
found  in  birds  which  possess  them  as  concavo-convex  plates  facing  outward. 

The  rostrum  of  the  sphenoid  is  a  hollow  subcylindrical  tube,  united  above  with 
the  interorbital  septum.  As  we  proceed  anteriorly  it  becomes  more  flattened  from 
side  to  side,  and  gradually  rises  upward.  At  a  point  about  half  way  between  the 
palatines  and  cranio-facial  hinge  it  terminates  in  a  process  directed  forward  ;  above 
this  is  the  sharpened  ethmoidal  margin,  nearly  perpendicular  to  the  long  axis  of 
the  skull.  Osseous  wings  to  the  ethmoid  never  develop  in  ISula,  not  even  rudi- 
mentary traces  of  them  being  seen  at  their  customary  sites. 

The  cranio-facial  hinge  is  exceedingly  perfect  in  its  construction,  being  composed 
of  a  thin  plate  of  bone  occupying  the  full  width  of  the  skull ;  the  bones  both  above 
and  below  are  separated  from  each  other  by  a  small  interval  for  the  entire  length  of 
the  transverse  line  constituting  the  hinge.  The  part  played  in  the  mechanism  by 
the  maxillaries  has  already  been  described  above. 

We  find  the  sphenotic  process  to  be  more  or  less  bifid  and  jutting  directly  out 
from  the  side  of  the  skull ;  on  the  other  hand,  the  mastoidal  process  is  a  crest  of 
bone  curling  forward.  Between  these  two  the  very  wide  crotophyte  valley 
is  seen. 

The  quadrate  is  a  large,  massive  bone,  with  its  mastoidal  head  composed  of  two 
prominent  ellipsoidal  trochlese,  separated  from  each  other  by  an  intervening  notch. 
Below  these  the  shaft  is  seen  to  be  rather  compressed  in  an  antero-posterior  direc- 
tion, and  supports  in  front  at  its  lower  half  an  unusually  formed  orbital  process. 
This  is  a  thin,  triangular  plate  of  bone  placed  in  the  vertical  plane,  and  with  its 
apex  directed  forward.  The  pneumatic  foramen  of  the  quadrate  usually  occurs  on 
the  posterior  aspect  of  the  shaft  in  most  birds,  but  here  it  is  situated  to  the  inner 
and  lower  side  of  this  orbital  process.  In  Sula  cyanops  I  find  two  others  on  the  an- 
terior aspect  of  the  bone,  one  near  each  articular  process. 

The  pit  for  the  quadrato-jugal  is  cylindrical  and  deep,  and  a  perforation  at  its 
bottom  may  lead  into  the  hollow  of  the  bone.  On  the  posterior  aspect  of  the  quad- 
rate we  find  an  irregular  facet  for  the  mandible;  it  looks  directly  to  the  rear  and 
stands  at  the  head  of  a  longitudinal  and  deep  groove  which  is  found  between  two 
similarly  placed  facets  on  the  foot  of  the  bone. 

Each  pterygoid  is  a  trihedral  and  compressed  bone  with  prominent  borders. 


SHUFELDT  :    OSTEOLOGY    OF   THE   STEGANOPODES  1-^5 

Regarding  this  skull  from  a  superior  view,  we  see  in  it  a  foramen  in  the  superior 
mandible,  near  the  site  of  the  narial  opening  of  the  majority  of  other  birds.  From 
this  aspect  we  also  have  a  good  view  of  the  wonderfully  perfect  cranio-facial  hinge 
of  this  bird. 

Posterior  to  this  is  a  broad,  smooth  area,  very  slightly  convex,  and  showing  in 
some  species  numerous  venations  like  those  on  the  bill  of  S.  cyanosis.  This  surface 
extends  from  the  cranio-facial  hinge  to  the  anterior  border  of  the  crotaphyte  fossa?, 
while  laterally  it  is  bounded  by  the  margins  of  the  orbits. 

This  view  also  shows  the  extent  and  form  of  these  crotaphyte  fossae,  and  how 
they  are  separated  from  each  other  in  the  median  line,  simply  by  an  extension 
backward  of  a  very  narrow  strip  of  the  general  surface  that  lies  beyond  them.  They 
merge  with  each  other  in  some  specimens  of  S.  piscator.  They  are  bounded  behind 
by  conspicuous  and  sharpened  crests  that  curl  slightly  forward,  and  are  best  marked 
laterally,  becoming  very  low  as  they  near  the  upper  part  of  the  supra-occipital 
prominence. 

The  under  view  of  the  skull  reveals  a  number  of  interesting  points.  We  find 
that  the  anterior  portions  of  the  palatines  are  parallel  to  each  other,  separated  by  a 
median  cleft  of  a  width  equal  to  either  one  of  them,  and  which  becomes  pointed 
behind. 

Their  anterior  ends  do  not  merge  into  the  premaxillary  beyond  until  they  are 
well  past  the  points  where  the  maxillaries  are  inserted.  These  anterior  portions  are 
thin,  horizontal  plates,  being  directly  continuous  with  the  horizontal  and  fused 
palatine  bodies  behind.  This  latter  portion  shows  a  small  median  carination  just 
in  front  of  the  united  heads,  and  the  postero-external  angles  are  rather  sharp,  being 
pointed  directly  backward. 

Anteriorly,  the  pterygoidal  heads  meet  each  other  and  the  fused  palatines,  the 
three  forming  a  groove  on  their  upper  sides  for  the  rostrum.  At  their  outer  ends 
each  pterygoid  offers  a  shallow  cup  to  form  the  usual  articulation  with  the  quadrate 
of  the  corresponding  side. 

Professor  Parker  found  that  "  in  Sida  alba  the  basitemporals  are  as  little  devel- 
oped as  in  the  Dromseidw,  less  than  in  any  other  carinate  bird.  Behind  each  moiety 
there  is  a  large  oval  opening,  not  far  in  front  of  the  occipital  condyle;  this  exposes 
the  loose  diplose  within.  The  small  Eustachian  tubes  open  at  a  little  distance  from 
each  other,  in  a  wide,  shallow  fossa,  on  the  part  where  the  three  elements  of  the 
parasphenoid  meet."  The  description  of  these  details  agrees  with  the  skull  of  the 
specimen  before  me.  Professor  Parker,  however,  was  fortunate  in  having  the  skele- 
ton of  the  ear-parts  in  his  specimen,  and,  of  them,  he  says  that  "in  Sula  alba,  the 


130  .  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

columella  auris  is  very  long  and  bent.  It  has  a  small,  cartilaginous,  extra-supra- 
stapedial  process,  and  a  long,  attenuated  stylohyal." 

On  either  side,  the  entrance  to  the  middle  ear  in  Sula  bassana,  as  in  others  of 
the  same  genus,  is  shallow,  and  it  is  situated  quite  internal  to  the  quadrate  bone, 
while  immediately  mesiad  to  it  there  is  a  pit  of  great  depth,  with  its  aperture  look- 
ing downwards,  and  its  base  in  the  vault  of  the  cranium,  which  seems  designed  for 
muscular  lodgment;  the  positions  of  the  usual  foramina  about  it  are  peculiar,  and 
extremely  interesting  in  these  birds. 

The  bony  wings  that  shield  the  entrance  to  the  ears  are  large  and  tilted  up 
behind.  Each  one  shows  the  double  facet  for  the  mastoidal  head  of  quadrate,  the 
outer  one  having  its  inner  margin  encroached  upon  by  the  pit  described  above. 

The  postero-internal  angle  of  either  of  these  wings  is  connected  with  the  side  of 
the  elevated  basi-temporal  region  by  a  bony  bar.  This  condition  can  best  be  seen 
from  a  posterior  view.  When  speaking  of  the  orbital  cavity  I  neglected  to  mention 
that  the  upper  part  of  the  septum  is  longitudinally  marked,  as  in  most  birds,  by  an 
open,  single  groove  for  the  passage  of  the  olfactory  nerve  to  the  rhinal  space  beyond. 
The  exit  for  it  from  the  brain-case  is  very  small,  indeed,  and  occasionally,  in  S. 
bassana,  on  one  side,  the  bone  spreads  over  it,  rendering  the  nerve  track,  for  a  frac- 
tion of  the  initial  part  of  its  course,  tubular. 

The  brain-box  itself  is  capacious  and  notable  for  its  great  width  over  its  com- 
pression in  the  vertical  direction.  Its  anterior  wall  looks  directly  downward  and 
forward,  making  an  angle  of  about  45  degrees  with  the  horizontal  palatine  bodies. 
Seen  from  behind,  the  skull  shows,  above,  the  extent  to  which  the  crotaphyte  fossa? 
approach  each  other  in  the  median  line  and  the  crest  that  divides  them  from  the 
occipital  area.  This  latter  has  the  usual  form  seen  among  these  cormorant-like 
birds,  constituting  an  arch  over  the  foramen  magnum,  which  occupies  the  center  of 
a  concavity  below  it.  The  supra-occipital  prominence  is  here  distinguished  by  a 
low,  smooth  median  ridge,  which  traverses  this  dome-like  elevation  from  the  inter- 
crotaphyte  line  to  the  superior  periphery  of  the  foramen  magnum. 

The  plane  of  this  latter  aperture  is  about  perpendicular  to  the  plane  of  the  basis 
cranii.  In  outline  the  foramen  is  broadly  elliptical,  with  the  short  axis  transverse. 
At  its  lower  margin  .we  see  a  large  ellipsoidal  condyle,  with  its  short  axis  at  right 
angles  with  that  of  the  foramen.  Below  this  again  are  the  oval  openings  in  the 
basi-temporal,  spoken  of  by  Parker,  with  the  prominent  descending  processes  of  this 
region  flanking  them  on  either  side. 

In  form,  the  inferior  mandible  is  spear-shaped,  its  sides  tapering  gradually  to  a 
sharpened  apex.  These  latter,  for  the  outer  aspects  of  their  anterior  two  thirds, 


SHUFELDT  :    OSTEOLOGY    OF   THE   STEGANOPODES  137 

show  the  same  character  of  venated  surface  as  I  described  for  the  superior  mandible. 
Posterior  to  this,  however,  as  well  as  the  inner  ramal  aspect,  the  bone  is  smooth, 
having  the  same  appearance  as  in  most  birds. 

The  symphysis  is  short  and  develops  a  spine  behind,  which  points  directly  back- 
ward and  is  in  every  respect  similar  to  the  process  in  the  same  place,  between  the 
sides  of  the  lower  jaw,  in  Herons  and  Albatrosses.  Each  ramus  of  this  mandible 
is  very  thick  from  side  to  side,  but  these  parts  are  hollow,  and  the  bone  as  a  whole, 
is  very  light,  owing  to  the  high  state  of  pneumaticity  it  enjoys. 

The  principal  foramina  for  the  entrance  of  air  to  its*  interior  are  four  in  number, 
two  on  either  limb,  one  being  to  the  mesial  side  of  the  articular  cup,  and  another 
larger,  longitudinally  piaced,  elliptical  one  just  beyond  this  concavity  on  the  inner 
aspect  of  the  ramus  near  its  upper  border.  The  superior  side  of  an  articular  end 
has  a  deep  excavation  at  its  center  upon  which  the  facets  for  the  quadrate  do  not 
encroach,  so  that,  when  the  jaw  is  articulated,  this  pit  comes  opposite  the  notch 
between  the  trochlese  of  the  mandibular  foot  of  the  quadrate,  creating  an  irregular 
hollow  space  there  between  the  bones  of  no  inconsiderable  size.  When  the  quad- 
rate thus  covers  it  there  are  two  entrances  that  are  left  open,  one  in  front  and  one 
behind,  close  to  the  pneumatic  foramen. 

The  mandibular  angles  are  truncate,  very  nearly  perpendicularly  so,  their  sur- 
faces being  concave  and  very  broadly  luniform  in  outline  (Plate  XXII.,  Fig.  7). 

Commencing  just  in  front  of  an  articular  cup,  we  find  the  superior  border  of 
the  ramus  to  be  rather  wide  and  rounded  as  far  as  the  meeting  with  the  dentary 
This  portion  presents  near  its  middle  a  double  coronoid  process,  one  being  in  front 
of  the  other.     The  dentary  portion  of  their  border  has  an  outer  cultrate  edge  and 
an  inner  and  somewhat  lower  rounded  one. 

The  outer  edge  goes  to  the  anterior  apex  of  the  symphysis,  the  inner  one  to  the 
hinder  termination  of  the  same,  while  between  the  two  a  nearly  horizontal  surface 
is  contained,  which  gradually  becomes  narrower  as  we  proceed  in  the  forward 
direction. 

The  lower  borders  of  the  mandible  are  rounded  for  their  entire  extent,  being 
produced  beneath  the-  articular  cups  and  continuous  with  the  inner  boundary  of 
either  truncate  angular  extremity. 

We  find  that  the  usual  bones  which  surround  the  true  ramal  vacuity  on  the 
side  of  the  mandible  in  many  birds,  here  interlock  with  each  other  so  as  to  com- 
pletely fill  the  fenestra  in,  but  in  rather  an  unusual  way,  and  apparently,  for  a 
definite  purpose;  for  each  ramus  presents,  both  on  its  inner  and  outer  side,  an 
oblique  slit,  these  slits  being  opposite  each  other  and  with  their  anterior  ends  in 


138  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

the  superior  border.  It  is  evident  that  this  otherwise  thick  jaw  is  much  weakened 
at  these  points  in  each  ramus,  and  this  occurs  just  posterior  to  the  hinder  termina- 
tion of  the  horny  sheath  of  the  lower  beak.  In  other  words,  the  hinder  moieties  of 
the  mandible  are  attached  to  the  anterior  or  dentary  portion  by  thin  plates  of  bone, 
consisting  principally  of  the  splenial  elements,  and  are  capable  of  being  bent  out- 
ward, which,  in  the  recent  specimen  can,  owing  to  the  way  the  quadrates  are 
attached,  be  effected  to  a  considerable  degree.  Now  in  life  these  oblique  slits  have 
their  anterior  ends  come  opposite  the  thin  anterior  insertions  of  the  maxillaries, 
and  these  latter  are  just  beneath  the  very  mobile  cranio-facial  hinge,  so  that  the 
whole  apparatus  is  admirably  arranged  to  permit  an  increase  in  size  of  the  fore  part 
of  the  buccal  cavity  when  a  Gannet  swallows  the  fish  that  constitutes  its  food,  and 
which  its  beak  is  so  well  fitted  otherwise  to  capture.  Moreover,  this  possible 
increase  in  caliber  takes  place  in  that  portion  of  the  digestive  tract  where  it  is  most 
needed,  or  where  the  bony  walls  of  the  mouth  would  prevent  the  admission  of  a 
very  large  morsel,  unless  some  such  mechanism  existed,  —  that  is,  at  the  very 
entrance  of  the  buccal  cavity,  and  just  posterior  to  the  more  horny  thecse  of  the 
beak.  In  Gannets,  however,  this  mobility  is,  to  some  extent,  restricted  by  the 
integumental  sheath  of  the  beak. 

Sulidse  have  a  wonderfully  pneumatic  skeleton,  the  entire  structure  enjoying 
that  condition,  save  the  ribs;  all  the  caudal  vertebra  (with  the  occasional  exception 
of  the  anterior  one)1;  and,  finally,  none  of  the  bones  of  the  pelvic  limb  are  pneu- 
matic below  the  femur.  The  entire  skeleton  of  the  wing  is  perfectly  so. 

In  a  specimen  of  Sula  gossi  before  me,  nine  or  ten  large  sderotal  plates  ossify  in 
either  eyeball,  and  these  overlap  each  other  much  as  we  find  they  do  in  other 
birds.  All  the  tracheal  rings  ossify  quite  perfectly,  as  do  the  bronchial  semirings  as 
they  approach  the  lungs.  These  rings  look  like  little,  narrow,  bony,  double-over- 
lapped straps,  as  they  are  arranged  in  situ  to  form  the  somewhat  antero-posteriorly 
compressed  windpipe.  The  usual  bones  of  the  superior  larynx  also  ossify,  and  in  the 
syringeal  portion  of  the  tube  we  find  strong  osseous  arcades  overarching  the  com- 
mencement of  either  bronchial  tube,  and  parallel  to  them  below,  in  the  median 
line,  the  dividing  pessulus  is  also  in  bone. 

Anatomists  have  long  known  that  the  hyoidean  apparatus  as  found  in  the  Sulidse 
is  invariably  a  very  much  aborted  affair.  The  only  parts  of  it  that  ossify  are,  first, 
a  little  irregular  piece  which  represents  the  first  basibranchial ;  and  second,  articu- 
lating with  this  behind,  are  two  simple  curved  rods  of  bone,  which  are  the  cerato- 
branchials  of  the  thyro-hyals.  Beyond  these,  no  part  of  the  tongue  of  a  Gannet 
ever  appears  to  ossify.  It  is  hardly  necessary  to  say  that  such  parts  of  the  skeleton 


SHUFELDT  :    OSTEOLOGY    OF   THE   STEGANOPODES  139 

as  the  sclerotal  plates,  the  tongue,  or  rings  of  the  trachea,  or  much  less  certain 
sesamoids  we  will  hereafter  he  called  upon  to  describe,  are  ever  pneumatic. 

Of  the  Remainder  of  the  Skeleton  of  the  Irunk  in  the  Sulidse.  (See  Plate  XXIII., 
Fig.  12.) 

In  the  common  Gannet  there  are  twenty-one  free  vertebne  in  the  spinal  column 
before  we  meet  the  one  that  first  anchyloses  to  form,  with  the  assistance  of  the  four- 
teen succeeding  ones,  a  sacrum  for  the  pelvic  bones.  Then  follow  seven  more  free 
ones,  devoted  to  the  movable  part  of  the  tail.  Finally,  we  have  a  long  pygostyle 
that  probably  contains  at  least  six  more.  Owing  to  the  lengthening  behind  of  its 
pelvic  bones,  the  sacrum  contains  sixteen  vertebrse  in  SuJa  cyanops,  and  that  species 
has  but  six  free  caudal  ones  plus  the  pygostyle. 

The  sixteenth,  seventeenth  and  eighteenth  vertebrse  support  each  a  pair  of  free 
ribs ;  the  next  three  belong  to  the  dorsal  series,  and  all  have  true  vertebral  ribs 
articulating  with  costal  ribs  from  the  sternum.  This  is  also  the  case  with  the  first 
three  pairs  that  spring  from  the  pelvic  sacrum.  The  ribs  on  the  sixteenth  vertebra 
are  exceedingly  rudimentary,  and  the  last  pair  of  "  floating  "  costal  ribs  have  no  cor- 
responding pair  of  vertebral  ones  above  them. 

In  mid-series  these  ribs  support  epipleural  appendages,  attached  in  the  usual  way 
to  their  posterior  borders.  (They  may  be  anchylosed  or  free.)  As  I  have  already 
stated  above,  they  are  completely  non-pneumatic. 

The  neural  canal  is  notable  for  being  nearly  cylindrical  throughout  the  first 
twenty-one  vertebrae.  It  is  only  at  the  region  of  the  enlargement  for  the  brachial 
plexus  that  it  is  rather  compressed  in  the  vertical  direction. 

The  atlas  has  a  minute  perforation  in  its  cup,  and  its  neural  arch  is  strikingly 
broad  and  deep.  The  axis  vertebra  possesses  a  stumpy  neural  spine,  and  its  hypa- 
pophysis,  directed  somewhat  backward,  is  very  prominent. 

The  odontoid  peg  is  comparatively  small  and  nearly  sessile  with  the  centrum, 
the  latter  presenting  a  concave  face  below  it. 

From  the  third  to  the  fourteenth  vertebra,  inclusive,  the  neural  spine  is  a  very 
inconspicuous  character,  while  from  this  on  it  gradually  makes  its  appearance,  increas- 
ing in  size  until  we  have  the  usual  quadrate,  longitudinal  plate  of  the  dorsal  series. 

The  third  and  fourth  vertebrse  have  each  a  prominent  hypapophysis  like  the 
one  on  the  axis,  but  in  the  fifth  this  feature  nearly  entirely  disappears. 

The  sixth  vertebra  is  faintly  marked  by  the  carotid  canal ;  this  gradually  be- 
comes more  and  more  tubular  in  the  seventh  and  eighth,  while  in  the  ninth  to  the 
thirteenth  inclusive  it  is  a  closed  cylindrical  canal  of  a  caliber  somewhat  less  than  the 
neural  canal  canal  above  it.  It  disappears  entirely  from  the  fourteenth  vertebra. 


140  MEMOIRS   OP   THE    CARNEGIE    MUSEUM 

The  lateral  canals  extend  from  the  third  vertebra  to  the  fifteenth,  inclusive ;  they 
are  short  in  any  of  the  segments,  and  their  posterior  apertures  are  far  larger  than 
their  anterior  ones. 

At  the  commencement  of  the  cervical  series  the  parial  parapophyses  are  short  and 
not  particularly  well  developed.  They  project  backward  from  the  inferior  walls  of 
the  lateral  canals,  but  as  the  carotid  canal  begins  to  develop,  these  processes  with- 
draw from  the  former  positions,  move  gradually  lower  down  beneath  the  centrum, 
and  at  the  same  time  increase  in  length  and  importance,  so  that  in  those  vertebrae 
where  the  carotid  canal  exists,  they  project  from  its  postero-inferior  border  directly 
backward  as  parallel  and  not  far  separated  spines. 

The  post-zygapophyses  do  not  appear  as  divergent  limbs  until  we  find  them  so  in 
the  eighth  vertebra;  in  all  the  cervical  segments  anterior  to  this  one  the  facets  are 
situated  on  the  inferior  aspect  of  the  tuberous  hinder  end  of  the  neural  arch  at  its 
lateral  angles. 

Metapophyses  are  seen  on  the  ninth  vertebra,  but  gradually  disappear,  to  be 
entirely  absent  in  the  fourteenth  or  fifteenth. 

The  transverse  processes  in  the  dorsal  region  are  broad,  flat,  and  horizontal,  being 
directed  more  and  more  to  the  rear  as  we  approach  the  pelvis.  The  plates  of  the 
neural  spines  above  do  not  meet  each  other  when  the  column  is  articulated,  and 
there  is  an  entire  absence  of  all  interlacing,  ossified  tendons  or  metapophyses  in  this 
region.  In  fact,  all  the  vertebra?  have  a  very  clean-cut,  non-angular  appearance, 
with  the  majority  of  projecting  borders  rounded. 

The  articular  ends  of  the  centra  are  constructed  upon  the  "  heterocselous  "  type; 
the  anterior  faces  in  the  ultimate  cervicals  and  leading  dorsals  being  notably  wide 
and  shallow,  and  often  riddled  with  foramina. 

The  pygostyle  and  the  free  caudal  vertebrae  will  be  spoken  of  after  the  pelvis  has 
been  described ;  in  the  meantime  we  will  turn  our  attention  for  a  few  moments  to 
the  description  of  the  sternum  and  pectoral  arch. 

The  Sternum. — This  bone  in  the  Gannets  has  a  very  peculiar  form.  A  pectoral 
aspect  of  the  bone  shows  that  the  body  has  an  oblong  figure  or  outline,  with  the 
average  width  nearly  equal  to  half  the  length.  Beyond  the  true  sternal  body  the 
anterior  portion  projects  as  a  massive  promontory,  and  a  large  part  of  the  carina  is 
beyond  this  again. 

The  anterior  moiety  of  the  bone  is  convex  upon  the  dorsal  side,  and  correspond- 
ingly concave  on  the  ventral  aspect.  Behind,  the  body  is  so  flattened  out  in  S.  bas- 
sana  as  to  be  nearly  horizontal.  The  costal  borders  look  outward  and  slightly  up- 
ward, and  each  usually  possesses  six  moderately  well-developed  facets  for  the  costal 


SHUFELDT:  OSTEOLOGY  OP  THE.  STEGANOPODES  141 

ribs.  In  a  specimen  of  8.  bassana,  however  (No.!l8045  U.  S.  Nat.  Mus.),  and  in  one 
of  S.  piscator  (No.  18739,  U.  S.  Nat.  Mus.),  I  find  but  five  of  these  facets  upon  either 
costal  border.  There  are  no  pneumatic  foramina  in  the  elongated  and  shallow 
intervals  between  them. 

The  principal  orifices  of  this  character  consist  in  a  diffuse  group  on  the  superior 
aspect  of  the  anterior  projecting  part,  within  the  general  concavity  of  the  bone. 

Either  costal  process  gracefully  rises  from  its  base  as  a  laminated  and  prominent 
horn,  curving  in  the  anterior  direction. 

The  posterior  moieties  of  the  lateral  borders  are  somewhat  rounded  and  extend 
almost  directly  backward  over  the  lateral  processes  behind. 

These  postero-external  xiphoidal  processes  are  very  long  and  wide,  being  rounded 
off  at  their  extremities  and  directed  a  little  outward.  They  are  narrowest  in  S. 
brewsteri,  more  flaring  in  S.  gossi,  and  very  wide  in  S.  cyanops. 

They  are  created  by  this  hinder  portion  of  the  bone  being  so  profoundly  one- 
notched  that  a  general  concave  mai'gin  has  resulted,  with  simply  a  median  papilli- 
form  process  remaining.  Even  this  latter  is  frequently  altogether  absent  in  S.  gossi, 
converting  the  posterior  sternal  border  in  this  species  into  one  long,  well-marked 
concavity. 

The  carina  juts  out  very  prominently  in  front  of  the  bone  ;  its  anterior  angle  is 
concave  from  above  downward,  and  develops  a  large  facet  for  the  furcula,  which  in 
life  articulates  with  it.  Above  this  the  border  is  again  concave  and  sharp,  while 
still  above  this  there  is  a  compressed  process  that  represents  the  manubrium.  This 
is  the  case  in  S.  bassana  only,  for  in  the  sternum  of  no  other  Gannet  before  us  is 
there  the  slightest  semblance  of  such  a  process  as  the  manubrium. 

The  lower  border  of  the  keel  is  straight  and  in  the  horizontal  plane,  being  capped 
off  with  a  spreading  rim.  This  border  merges  into  the  surface  of  the  body  of  the 
bone  before  it  halfway  reaches  the  xiphoidal  notch. 

The  sides  of  the  keel  are  smooth,  and  neither  it  nor  the  under  side  of  the  sternal 
body  show  in  this  specimen  any  of  the  muscular  lines  usually  present  in  most  birds. 

A  broad  median  notch,  concave  from  side  to  side,  convex  from  before  backward, 
lies  between  the  lofty  superior  portions  of  the  coracoidal  grooves.  These  latter  meet 
in  front  of  it,  while  behind,  its  surface  becomes  directly  continuous  with  the  general 
surface  of  the  upper  side  of  the  body,  and  that  where  the  group  of  pneumatic  foram- 
ina are  found. 

A  coracoidal  groove  looks  forward  and  outward  for  its  upper  portion,  directly 
upward  for  its  lower,  and  extends  rather  less  than  half  way  between  the  base  of  the 
costal  process  and  the  median  line.  It  consists  of  two  portions  which  are  directly 


142  MEMOIRS   OF   THE    CARNEGIE    MUSEUM 

continuous  with  each  other.  The  lower  one  is  a  shelf-like  projection  with  a  convex 
border  forward  and  its  articular  surface  in  the  horizontal  plane.  Immediately 
above  this  rises  a  much  broader  surface,  though  not  so  long,  which  is  decidedly  con- 
vex from  above  downward.  This  portion  of  the  facet  for  the  coracoid  is  consider- 
ably higher  than  the  plane  in  which  the  borders  of  the  body  of  the  bone  are  found. 
It  faces  forward  and  outward,  and  has  one  regular  convexity  as  its  limiting  margin 
above.  Between  the  point  of  its  outer  termination  and  the  apex  of  the  correspond- 
ing costal  process,  the  border  is  one  sweeping  concavity. 

This  form  of  sternum  is  more  or  less  peculiar  to  the  Sulidx,  and  it  departs  in  a 
number  of  points  from  the  form  of  the  sternum  of  the  Cormorants  and  of  the  Peli- 
cans. Comparatively,  the  bone  is  not  so  long  in  Sula  gossi  as  it  is  in  S.  bassana,  S. 
breivsieri  and  other  species.  Still  the  general  pattern  of  the  sternum  is  much  the  same 
throughout  the  Sulidse.  If  we  overlook  the  crossing  of  the  coracoidal  grooves  in 
the  sternum  of  Phaethon  xihereus,  and  its  having  a  manubrium,  there  is  a  great 
deal  in  the  bone  to  remind  us  of  the  sternum  of  Snla  gossi — and,  in  fact,  there  are 
more  steganopodous  characters  in  the  sternum  of  the  Tropic  Bird  than  there  are  of 
any  other  avian  group  with  which  I  am  at  present  acquainted. 

Of  the  Shoulder-girdle.  —  (Plate  XXIIL,  Fig.  12.)  This  part  of  the  skeleton  is, 
like  so  much  of  the  rest  of  it,  thoroughly  pneumatic,  the  foramina  occurring  at 
their  usual  sites. 

The  clavicles  form  a  broad  U-shaped  arch,  being  completely  united  below,  Avhere, 
at  the  median  point  beneath,  they  support  an  extensive  facet  for  articulation  with 
the  carinal  angle  of  the  sternum.  This  does  away  with  any  such  thing  as  a  hypo- 
cleidium  proper,  notwithstanding  the  fact  that  the  bone  projects  slightly  over  this  facet. 

The  clavicular  limbs  are  compressed  from  side  to  side,  broader  above  than  below, 
with  their  anterior  and  posterior  borders  rounded  off. 

A  clavicular  head  is  also  compressed  in  the  same  manner  as  its  shaft,  and 
tapers  off  as  a  pointed  process. 

The  most  striking  feature  of  this  part  of  the  bone  is,  however,  the  extraordi- 
nary facet  it  supports  to  articulate  with  the  coracoid.  Either  one  of  these  is  situated 
at  its  outer  side,  upon  a  promontory  of  bone  which  is  found  there,  the  latter  being 
of  a  proper  form  to  receive  it.  The  facet  is  of  an  elliptical  outline,  placed  vertically, 
and  facing  directly  backward.  Something  of  a  notch  is  found  between  it  and  the 
clavicular  head,  in  which  occurs  a  number  of  the  principal  pneumatic  foramina  of 
the  furcula.  On  the  anterior  surface,  just  below  the  summit  of  a  coracoid,  we  find 
a  distinct  elliptical  facet  for  articulation  with  a  similar  one  just  described  for  the 
fourchette.  Between  this  and  the  ear-shaped  glenoid  facet  a  considerable  valley 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  143 

is  found.  On  the  opposite  side  of  the  coracoidal  head  we  find  a  group  of  pneumatic 
foramina,  and  below  these  a  peculiarly  formed  scapular  process,  a  spine-like  apo- 
physis,  which  rather  gracefully  curls  upward  and  then  toward  the  shaft  of  the  bone. 
This  latter  portion  of  the  bone  is  subcylindrical  and  smooth,  dilating  below  into 
a  transverse  fan-shaped  sternal  extremity. 

A  scapula  offers  but  a  very  small  portion  of  the  articular  surface  for  the  glenoid 
cavity  ;  not  more  than  an  eighth  of  it  in  all  the  specimens  examined  by  me.  The 
head  of  the  bone  then  reaches  forward  and  inward,  but  only  the  outer  two  thirds 
of  this  makes  an  indifferent  articulation  with  the  narrow  and  roughened  border  of 
the  scapular  process  of  the  coracoid.  The  shaft  of  the  bone  is  quite  stout  behind 
this  and  somewhat  compressed  in  the  vertical  direction,  while  posteriorly  it  flat- 
tens out  into  a  broad  paddle-shaped  extremity  that  finally  tapers  to  a  point 
behind. 

Even  more  than  it  is  in  the  case  of  the  sternum,  the  bones  of  the  shoulder-girdle 
in  all  the  species  of  the  Sulidas  at  my  hand  are,  apart  from  their  specific  variance  in 
size,  almost  identically  alike  in  each  and  every  one  of  their  corresponding  characters. 
As  for  the  bones  of  the  shoulder-girdle  in  the  PhaWionidse,  we  may  say  here,  by  way 
of  comparison,  that  it  is  only  in  the  scapula  where  we  see  the  characters  which  more 
or  less  resemble  the  corresponding  ones  as  we  find  them  in  the  scapula?  of  the  Sulidx. 
Neither  the  os  furcula  nor  a  coracoid  of  a  gannet  or  booby  bear  any  special  resem- 
blance to  those  bones  as  they  exist  in  the  tropic  birds. 

Of  the  Pelvis  and  Caudal  Vertebrse. — The  first  vertebra  that  anchyloses  with  the  pelvic 
sacrum  anteriorly  projects  entirely  beyond  the  iliac  bones.  Its  centrum,  in  common 
with  the  next  three  that  follow  it,  is  much  compressed  from  side  to  side,  and  its  neural 
spine  is  continuous  with  the  common  neural  ridge  above  the  succeeding  segments. 

The  first  five  vertebne  that  lie  beneath  the  ilia  throw  out  their  apophyses  in  the 
usual  way  for  their  support ;  the  last  two  of  this  series  meet  the  iliac  margins. 
Here  the  neural  canal  and  centra  are  large,  in  order  to  afford  room  for  the  increase 
in  size  of  the  cord  where  the  sacral  plexus  is  thrown  off. 

The  twenty-eighth  and  twenty-ninth  vertebrae  have  their  processes  thrown  directly 
upward,  so  that  they  are  scarcely  visible  upon  direct  ventral  aspect. 

In  the  thirtieth  vertebra  they  are  powerfully  developed  and  extend  directly 
across  the  basin  to  abut  by  anchylosis  against  the  pelvic  walls  immediately  behind 
the  cotyloid  cavity  on  either  side.  From  this  point  the  centra  of  the  so-called  uro- 
sacral  vertebras  taper  quite  rapidly  in  size  to  the  ultimate  one,  which,  in  S.  bassana, 
is  enlarged  and  exhibits  a  big  facet  on  its  posterior  aspect,  intended  for  the  first  free 
caudal.  In  S.  piscator  this  enlargement  is  not  evident. 


144  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

The  extremities  of  their  diapophyses  anchylose  in  a  very  thorough  manner  with 
the  inner  iliac  margins,  and  a  lateral  view  shows  their  sides  to  be  riddled  with  pneu- 
matic foramina  between  these  processes. 

Viewing  this  pelvis  from  above,  we  notice  that  the  entire  inner  margins  of  the 
iliac  bones  have  merged  into  and  completely  anchylosed  with  the  sacrum.  This 
converts  the  ilio-neural  grooves  into  ilio-neural  canals  and  gives  the  bone  a  very 
compact  appearance.  The  anterior  margins  of  the  ilia  are,  rounded,  and  are  set  off 
with  rather  a  deep  and  raised  emargination  in  S.  bassana,  which  is  feebly  marked  in 
S.  piscator  and  other  species. 

The  post-  and  pre-acetabular  surfaces  are  about  equal  in  the  extent  of  their  su- 
perficial areas,  except  in  Sula  cyanops,  where  the  postacetabular  area  is  the  more 
extensive. 

The  anterior  iliac  surfaces  are  concave  on  either  side,  and  each  faces  upward 
and  outward  to  about  an  equal  degree.  Sula  piscator  here  offers  another  exception, 
and  in  this  species  the  pelvis  is  comparatively  shorter,  as  well  as  broader  and  flatter 
than  it  is  in  other  species  of  Gannets. 

Elevated  above  these  anterior  iliac  concavities  we  find  the  postacetabular  area  to 
be  nearly  horizontal.  Large  elliptical  foramina  are  found  between  the  apophyses 
of  the  last  three  or  four  uro-sacrals,  and  these  latter,  likewise,  develop  quite  a 
prominent  neural  crest. 

Upon  the  lateral  aspect  of  this  pelvis  we  find  a  very  large  cotyloid  ring,  the 
inner  margin  of  which  is  fully  equal  in  size  to  the  outer.  A  moderately  sized  anti- 
trochanter  occupies  its  usual  site,  with  its  articular  surface  directed  downward, 
forward  and  outward. 

Behind  this  occurs  an  enormous  elliptical  ischiadic  foramen,  that  occupies  nearly 
all  of  this  post-ace  tabular  lateral  aspect.  Through  the  fenestra  thus  formed  we  are 
enabled  to  get  a  good  lateral  view  of  the  uro-sacral  vertebra?  and  the  extensive 
pneumatic  condition  they  enjoy. 

The  lower  margin  of  the  ilium  is  sharp  and  convex  ;  it  forms  the  superior  boun- 
dary to  a  long,  narrow,  obturator  space,  which  opens  freely  into  the  rather  small 
obturator  foramen. 

A  pro-pubis  does  not  develop  in  the  Gannets,  while  the  post-pubis  is,  for  the  most 
of  its  extent,  fragile  and  slender.  It  begins  to  increase  in  size  just  before  arriving 
at  a  point  opposite  the  end  of  the  ischium.  At  this  point  it  offers  a  small  facet  on 
its  upper  margin  for  the  ischiadic  postero-inferior  angle,  and  the  two  bones  are  in 
contact  here  during  life.  The  post-pubis,  retaining  its  increase  in  size,  then  curves 
inward  toward  the  fellow  of  the  opposite  side,  to  terminate  in  a  cartilaginous  tip. 


SHUFELDT  :     OSTEOLOGY    OF    THE   STEGANOPODES  145 

The  posterior  border  of  this  lateral  aspect  shows  a  well-marked  ilio-ischiadic  notch 
at  about  the  middle  of  its  extent.  This  character  is  best  marked  in  S.  cyanops  and 
S.  gossi,  being  much  shallower  in  other  species,  especially  in  S.  piscator.  The  outer 
side  of  the  bone  between  it  and  the  ischiadic  foramen  is  directed  upward  as  well  as 
outward. 

As  has  already  been  mentioned  above,  there  are  usually  seven  free  vertebrae  plus  a 
large  pygostyle  in  the  skeleton  of  the  tail  of  most  Gannets  and  Boobies,  but  an 
exception  is  noted  in  the  case  of  Sula  cyanops,  in  which  species  I  count  in  the 
specimen  before  me,  only  six  and  the  pygostyle.  The  characters  of  these  vertebras 
may  be  well  studied  in  the  skeleton  of  the  tail  in  Sula  brewsteri.  What  first  strikes 
one  upon  glancing  at  this  part  of  the  osseous  system  of  any  Gannet  is  its  compara- 
tive massiveness,  the  great  size  of  the  individual  vertebrae,  and  the  large  pygostyle. 
The  neural  spines  however,  are  short  and  stumpy;  in  Sula  bassana  they  are  occasion- 
ally bifid  anteriorly.  The  neural  arches  beneath  them  close  over  the  spinal  canal  for 
the  entire  length  of  the  series,  and  the  latter,  for  a  short  distance,  is  seen  to  perforate 
the  pygostyle.  The  transverse  processes  are  thick  and  strong,  being  very  wide-spread- 
ing, especially  in  the  case  of  the  ultimate  and  penultimate  free  ones.  From  four  to 
five  of  the  last  ones  usually  develop  haemal  spines.  These  become  larger  as  we 
approach  the  pygostyle,  the  first  vertebra  of  which  also  has  one,  it  being  bifid, 
and  hooking  forward,  as  do  those  on  the  caudals  in  front  of  it.  The  interarticular 
facet  on  the  faces  of  the  centra  are  nearly  flat,  showing  barely  any  concavity  or 
convexity. 

The  pygostyle  appears  to  be  composed  of  about  six  vertebrae,  of  which  the  three 
anterior  ones  can  be  quite  easily  made  out.  It  has  a  very  unusual  form  in  this  bird, 
being  very  long  and  subconical,  with  sharp  superior  border  and  rather  decurved 
apex.  Below,  it  is  broad  and  somewhat  convex.  Viewing  it  from  in  front  we  notice 
that  it  has  all  the  elements  present,  though  in  very  rudimentary  state,  of  one  of  the 
caudal  vertebra),  including  the  large,  prominent  and  anchylosed  haemal  spine  just 
mentioned. 

TJie  Appcndicular  Skeleton. 

The  Pectoral  Limb.  —  We  find  the  humerus  in  Sula  bassana  to  be  somewhat  longer 
than  the  radius  and  ulna  in  this  limb,  but  we  shall  see  later  on  that  this  varies 
greatly  in  the  other  species.  I  will  write  out  here  first  an  account  of  the  appendic- 
ular  skeleton  of  Sula  bassana,  and  close  with  the  differences  exemplified  on  the 
part  of  the  other  Gannets  and  Boobies  we  have  under  consideration.  In  this 
humerus  the  ulnar  crest  is  prominent  and  projecting,  though  rather  inclined  to  retreat 
from  the  elongated  and  shallow  pneumatic  fossa  that  arches  over  it,  as  in  many  other 


146  MEMOIRS    OF   THE    CARNEGIE    MUSEUM 

water  birds.  The  radial  crest  is  reduced  to  a  long,  low,  inconspicuous  ridge,  and, 
in  fact,  this  proximal  end  of  the  humerus,  as  a  whole,  merges  into  the  shaft  so 
gradually  from  both  sides,  and  its  being  so  narrow  withal,  that  we  are  rather  im- 
pressed with  its  lack  of  strength  and  an  absence  of  a  certain  robustness  so  characteristic 
of  the  bone  in  other  birds  of  equal  size  and  that  lead  a  similar  life.  This  in  no  way 
applies,  however,  to  the  shaft  itself,  for  this  subcylindrical  and  hollow,  bony  tube,  with 
its  double  sigmoidal  curve,  carries  with  it  the  very  elements  of  strength  and  power. 

Its  distal  extremity  lacks  but  little  of  being  as  wide  as  the  widest  part  of  the 
head  of  the  bone.  It  is  without  an  ecto-condyloid  process,  has  the  trochlese  very 
prominent,  and  presents  for  examination  a  deep  fossa  to  the  anconal  side  of  the 
ulnar  tubercle. 

The  shaft  of  radius  for  so  long  a  one  is  unusually  straight,  and  only  a  slight 
curve  is  noticed  in  the  proximal  moiety  of  the  ulna. 

In  its  continuity  the  former  bone  is  subtrihedral  in  its  form,  with  its  pneumatic 
foramina  situated  beneath  the  transversely  expanded  portion  of  the  distal  end. 
Muscular  lines  mark  this  radial  shaft  along  its  inferior  aspect. 

For  its  distal  moiety  the  shaft  of  ulna  is  nearly  cylindrical  in  form,  but  this  is 
gradually  exchanged  for  the  subtrihedral  as  we  pass  over  the  proximal  half  of  the  bone. 

It  presents  for  examination  a  double  row  of  feebly  marked  papillae  for  the  quill- 
butts  of  the  secondary  feathers. 

A  long,  shallow,  though  notable  fossa  is  seen  at  the  proximal  and  anconal  side 
of  the  shaft,  which  terminates  in  a  single  pneumatic  foramen  just  beyond  the  promi- 
nent cup-shaped  articulation  for  the  ulnar  tubercle  of  the  humerus. 

Other  pneumatic  holes  occur  at  the  distal  end  of  the  ulna  upon  all  sides,  except 
the  outer  one.  The  olecranon,  though  large  and  rather  tuberous,  would  not  particu- 
larly attract  our  attention.  A  distinct  canal  upon  the  outer  aspect  of  the  distal 
end  of  the  shaft  for  the  passage  of  the  tendons  characterizes  this  bone.  The  artic- 
ular surface  shows  nothing  of  special  interest. 

As  usual,  the  carpal  segments  are  but  two  in  number  —  a  radiale  and  an  ulnare. 
They  present  the  forms  and  facets  common  to  these  bones  generally.  Both  are 
pneumatic  and  have  large  apertures  for  the  admission  of  air  to  their  hollow  interiors. 

The  carpo-metacarpus  also  presents  a  number  of  those  foramina  at  either  of  its 
extremities;  the  principal  one,  however,  is  found  just  below  the  trochlear  surface 
formed  by  os  magnum  upon  the  anconal  side  of  the  bone.  A  notable  process  occurs 
immediately  below  it,  as  well  as  another  group  of  these  air-holes,  in  its  outer  as- 
pect, near  the  short  and  inconspicuous  first  metacarpal. 

The  main  shaft  is  straight  and  of  good  caliber ;  on  the  palmar  side  it  is  longitudi- 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  147 

nally  grooved  nearly  its  entire  length  for  a  tendon  going  to  the  fingers.  This  is  best 
marked  upon  the  distal  moiety  of  the  bone.  The  metacarpal  of  the  middle  digit  is 
also  straight  for  the  major  extent  of  its  course;  its  extremities  becoming  enlarged  in 
order  to  allow  it  to  make  the  usual  connections  with  the  metacarpal  index.  It  is 
rather  slender  and  develops  no  special  processes,  as  it  sometimes  does  in  other  rep- 
resentatives of  the  class. 

The  expanded  portion  of  the  proximal  joint  of  the  index  digit  is  not  perforated, 
not  even  by  the  numerous  pneumatic  foramina  which  are  irregularly  scattered 
over  its  surface.  Below  it  is  produced  us  a  notable  process,  and  a  process  that  is 
seen  in  some  of  the  extinct  birds,  as,  for  instance,  in  Ickthyornis.  The  shaft  of 
this  phalanx  is  broad  and  fiat  anteriorly,  and  perfectly  straight  from  above  down- 
ward. 

Equal  to  half  the  length  of  the  carpo-metacarpus,  the  distal  phalanx  of  the  index 
digit  is  of  a  trihedral  form,  with  an  extensive  excavation  at  the  posterior  aspect 
of  its  proximal  end,  which  is  continued  in  a  lesser  degree  the  entire  length  of  the 
bone.  It  bears  no  claw  below,  but  is  finished  off  by  a  distinct  little  process. 

The  pollex  phalanx  has  very  much  the  same  form  as  the  one  just  described,  but 
it  lacks  the  longitudinal  excavation  down  its  posterior  aspect.  Both  of  the  bones  are 
pneumatic.  Lastly,  we  have  the  smallest  phalanx  of  all,  belonging  to  the  middle 
finger.  This,  as  usual,  is  behind  the  broad  proximal  joint  of  the  index,  and  not 
quite  equal  to  half  its  hinder  border  in  length. 

Now  the  general  characters  of  the  bones  of  the  pectoral  limb  are,  in  Stda  cyanops, 
S.  piscator,  S.  gossi  and  S.  brewsteri,  in  the  main  about  the  same  as  they  have  just 
briefly  been  given  for  Sula  bassana.  We  find  differences,  to  be  sure,  but  they  are 
very  slight.  The  humerus  in  S.  cyanops  closely  resembles  that  bone  in  S.  bassana, 
only  it  is  considerably  smaller  in  the  first-named  species.  Occasionally  about  the 
proximal  end  of  the  carpo-metacarpus  the  position  and  size  of  the  pneumatic  open- 
ings may  vary,  but  that  is  often  seen  to  be  the  case  in  all  large  birds  with  highly 
pneumatic  skeletons. 

In  S.  piscator  the  olecranon  fossa  of  the  humerus  is  comparatively  larger  and 
with  better  defined  borders  than  it  has  in  S.  bassana.  This  is  likewise  the  case  in 
Sula  gossi  and  S.  brewsteri,  in  both  of  which  species  that  fossa  is  especially  well 
marked.  Beyond  such  trivial  departures  as  these,  we  meet  with  little  or  nothing 
worthy  of  formal  record.  Individual  specimens  of  the  same  species,  however,  vary 
a  little ;  take,  for  example,  the  carpo-metacarpus.  It  is  seen  to  be  rather  smaller 
than  that  of  another  specimen  of  the  same  species  of  S.  bassana  now  at  my  hand  for 
comparison. 


148 


MEMOIRS   OF   THE    CARNEGIE   MUSEUM 


Where  remarkable  differences  do  come  in,  is  in  the  relative  lengths  of  these  bones 
when  we  come  to  compare  them  in  one  species  with  the  corresponding  bone  in  an- 
other. In  speaking  of  Sula  bassana,  I  said  above  that  its  humerus  was  longer  than 
the  radius  or  ulna ;  now  this  is  not  the  case  in  other  species  of  Gannets,  as  the  sub- 
joined table  will  plainly  show. 

MEASUREMENTS  IN  CENTIMETERS  AND  FRACTIONS. 


Species. 

Humerus. 

Ulna. 

Carpo-metacarpus. 

Joints  of  Index 
Digit. 

Sula  bassana. 

23.5 

20.4 

9.6 

9.6 

Sula  cyanops. 

19.3 

20.7 

8.8 

8.1 

Sula  piscator. 

17.1 

18.4 

7.2 

6.9 

Sula  gossi. 

16.2 

17.3 

7.6 

6.9 

Sula  brewisteri. 

18.4 

19.8 

8.1 

7.6 

Of  the  Pelvic  Limb. — In  comparison  with  the  general  size  of  Sula  bassana  the 
lower  extremity  is  very  short/though  the  bones  composing  its  skeleton  are  none  the 
less  strong  in  consequence.  In  the  femur  we  find  the  axis  of  the  head  and  neck 
making  an  angle  with  the  longitudinal  axis  of  the  shaft.  The  head  is  quite  dis- 
tinct, globular,  and,  as  usual,  excavated  on  top.  Its  surface  is  continual  with  the 
broad  articular  surface  which  occupies  the  entire  summit  of  the  bone.  ISTo  trochan- 
terian  ridge  rises  above  this  latter,  and,  indeed,  this  character  of  the  femur  is  but 
poorly  developed. 

A  pneumatic  foramen  is  always  seen  at  its  most  common  site,  on  the  anterior 
aspect,  just  below  the  superior  articular  surface. 

The  shaft  is  cylindrical,  roughened  in  some  places  by  lines  and  diffuse  tuberosi- 
ties  for  muscular  attachment,  and  is  bent  slightly  to  the  front  and  somewhat  to  the 
inner  side.  At  its  distal  extremity  the  condyles  are  fashioned  after  the  usual  pattern 
among  birds,  but  all  their  characters  in  Sula  present  a  sort  of  lack  of  strong  devel- 
opment. The  fibular  cleft  is  but  faintly  marked,  the  intercondyloid  notch  or  fossa 
is  shallow,  and  the  ridges  in  front  much  rounded  and  inconspicuous. 

Something  of  the  same  condition  is  extended  to  the  proximal  end  of  the  tibio- 
tarsus  of  the  leg,  though  not  to  such  a  marked  degree.  Here  the  cnemial  process  rises 
but  slightly  above  the  articular  summit  of  the  bone,  and  the  pro-  and  ecto-cnemial 
ridges  which  descend  below  it  soon  merge  into  the  shaft,  and  are,  at  the  best  not 
very  prominently  developed. 

The  shaft  of  this  bone  is  straight  and  smooth  and  somewhat  compressed  through- 
out from  before  backward.  It  offers  a  long  ridge  to  the  fibula  and  is  broad  across 
where  it  is  found.  The  distal  extremity  of  the  bone  evinces  more  character  than 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  149 

the  proximal  one.  An  oblique  bridge,  to  confine  the  extensor  tendons,  is  extended 
across  the  deep  groove  that  contains  them  during  life.  Nearly  parallel  with  each 
other,  the  condyles  are  wide  apart,  prominent  and  convex  in  front,  to  become  sup- 
pressed and  low  and  thin-crested  behind. 

The  fibula  has  the  usual  form  seen  in  birds,  but  is  here  particularly  interesting 
from  the  fact  that  it  does  not  anchylose  with  the  shaft  of  the  leg-bone  until  it  arrives 
at  the  middle  of  its  lower  third,  and  even  from  this  low  point  the  remainder  of  the 
bone,  including  an  oval  "external  malleolus,"  stands  out  quite  prominently.  This 
rare  condition  of  things  has  been  pointed  out  also  by  me  as  occurring  in  Uri- 
nator  lumme. 

Sala  bassana  has  a  long  oval  patella,  obliquely  marked  across  its  anterior  surface 
by  a  groove  for  the  tendon  of  the  ambiens  muscle. 

The  tarso-metatarsus  in  Sula  is  strikingly  large  in  its  proportions  when  compared 
with  the  other  bones  of  the  limb.  In  length  it  is  a  little  more  than  half  as  long 
as  the  tibiotarsus,  but  being  wider  and  broader  it  appears  much  more  massive.  Its 
hypo-tarsus  presents  three  short,  longitudinal  elevations  of  unequal  sizes.  These 
inclose  two  tubular  passages  for  tendons,  and  are  grooved  themselves  besides.  In 
other  specimens  they  are  flat,  and  the  two  outer  elevations  may  posteriorly  meet, 
thus  creating  a  vertical  perforation  rather  than  a  groove.  The  back  of  the  shaft  is 
flat,  but  in  front  it  is  much  scooped  out  above,  where  it  shows  two  antero-posterior 
perforations. 

At  the  distal  extremity  three  large  trochlear  projections  present  themselves. 
They  are  separated  from  one  another  by  wide  clefts  of  about  an  equal  depth.  These 
trochleje  are  placed  nearly  side  by  side,  the  middle  one  being  the  lowest  down,  the 
inner  next,  and  the  outer  one  the  most  elevated.  Their  median  grooves  are  best 
marked  behind,  but  in  addition  the  internal  trochlea  presents  a  deep,  vertical  notch 
upon  its  outer  aspect. 

The  usual  arterial  perforation  pierces  the  bone  above  the  cleft  found  between  the 
outer  and  middle  projections,  a  groove  leading  into  it  from  above. 

The  accessory  metatarsal  is  rather  an  elongated  bone,  swung  in  the  usual  way 
by  ligaments  to  the  lower  part  of  the  shaft. 

The  basal  joint  of  the  hallux,  which  it  supports,  is  comparatively  more  slender 
for  its  length  than  the  other  joints  of  the  foot. 

For  the  three  anterior  toes  these  latter  are,  in  number  and  arrangement,  the  same 
as  in  the  vast  majority  of  the  class.  They  present  all  the  characters  usually 
attributed  to  the  phalanges  of  the  podal  digits  in  birds,  and  are  well  proportioned, 
both  as  regards  their  relative  calibers  and  lengths. 


150 


MEMOIRS    OF   THE    CARNEGIE    MUSEUM 


The  pneumatic  foramen  in  the  femur  of  S.  cyanops  is  usually  very  large,  and 
comparatively  small  in  my  specimen  of  S.  piscator.  This  also  applies  to  S.  brewsteri, 
but  in  Sula  gossi  it  is  notably  very  large  again.  The  general  characters  of  the  femur 
are  much  alike  in  all  typical  Gannets. 

The  ti bio-tarsus  and  fibula  in  Sula  cyanops  agree  with  those  bones  in  S.  bassana, 
as  they  practically  do  in  other  species.  There  is  a  difference  seen  in  the  degree  of 
distinctness  of  the  distal  end  of  the  fibula.  The  entire  bone  can  easily  be  made  out 
in  all  my  specimens  of  S.  gossi,  and  only,  or  less  than,  the  distal  fourth  of  it  fuses 
with  the  tibio-tarsus  in  that  species.  The  tibio-tarsal  condyles  are  far  apart  in  S. 
piscator  and  S.  gossi,  and  in  most  birds  of  this  family  this  character  is  more  evident 
than  it  is  in  S.  bassana.  In  this  last-named  species  the  tibio-tarsus  and  tarso-meta- 
tarsus  are  all  non-pneumatic ;  I  fail  to  find  any  pneumatic  openings  in  the  tibio- 
tarsus  of  8.  cyanops,  but  the  tarso-meta tarsus  of  that  species  enjoys  that  condition 
to  a  very  high  degree,  as  numerous  and  large  air-holes  are  found  about  the  head 
of  the  bone.  Another  remarkable  fact  is  that  the  tarso-metatarsus  in  Sula  cyanops 
is  rather  larger  than  that  bone  in  Sula  bassana.  It  is  very  small  in  S.  piscator,  and 
in  all  considerable  variation  may  exist  in  the  hypotarsus,  for  the  places  where  the 
tendons  pass  through  may  be  either  grooves  or  perforations.  Whatever  they  are, 
however,  they  never  exceed  two  in  number.  Below  I  give  a  table  showing  the  com- 
parative lengths  of  these  bones  in  the  species  under  consideration. 

MEASUREMENTS  IN  CENTIMETERS  AND  FRACTIONS. 


Species. 

Femur. 

Tibia. 

Tarso-inetatarsus. 

Middle  Anterior 
Toe. 

Sula  bassana. 

7.4 

10.9 

6.1 

Sula  cyanops. 
Sula  piscator. 
Sula  gossi. 

6.4 
4.9 
5.4 

9.9 
6.9 
7,9 

6.5 
3.8 
4.9 

7.9 

Sula  brewxteri. 

5.9 

9.1 

5.7 

8.3 

From  this  study  it  is  hardly  necessary  to  add  that  the  skeleton  of  the  pectoral 
and  pelvic  limbs  of  the  SulidiK  is  entirely  different  from  the  corresponding  parts  and 
bones  in  the  Pha'ethonidte. 

ANHINGID.E. 

Osteology  of  Anhinga  anhinga. 

As  will  be  seen  by  my  list  of  material  given  above,  I  have,  at  the  present  writ- 
ing, but  a  single  skeleton  of  this  family  of  birds,  before  me  for  examination.  It  is 
complete,  however,  and  there  are  at  hand  the  accounts  of  the  osteology  of  Plotus 
by  other  authors.  Doctor  R.  Bowdler  Sharpe  in  his  recent  Hand  List  of  Birds 


SHUFELDT  :     OSTEOLOGY    OF    THE   STEGANOPODES 


151 


(1899)  retains  all  the  Anhingas  in  the  family  Plotidx,  and,  in  addition  to  two  fossil 
forms,  recognizes  our  existing  species,  viz :  P.  rufus,  P.  melanogaMer,  P.  novie- 
hollandise,  and  P.  anhinga.  The  Arihinga  anhinga  is  the  sole  representative  of  this 
family  in  the  United  States.  A  peculiarity  of  the  skeleton  of  Anhinga  is,  it  is 
almost  completely  non-pneumatic.  It  is  only  into  the  base  of  the  cranium  and  the 
articular  ends  of  the  mandible  that  air  gains  access  through  minute  foramina  occu- 
pying the  usual  sites. 

Of  the  Skull. — This  bird  has  a  very  perfect  "  cranio-facial  hinge,"  and  measuring 
each  way  from  the  center  of  it  we  find  the  superior  mandible  to  be  about  1.5  cm. 
longer  than  the  cranium.  In  form  the  superior  mandible  is  long,  narrow  and  spear- 
shaped,  being  drawn  out  to  a  sharp  point.  It  is  nearly  straight.  Beneath,  it  is  flat 
with  cultrate  tomia.  The  culmen  is  rounded  off,  and  the  nasals  have  so  fused  with 
the  surrounding  bones  of  the  face  that  most  of  the  sutural  lines  cannot  be  dis- 
tinguished in  the  adult.  Where  the  external  nostrils  would  naturally  occur,  there 
are  usually  present  only  minute  holes  that  do  not  appear  to  reach  in  so  far  as  the 
rhinal  chamber.  Viewed  from  above,  we  are  to  observe  that  the  cranial  and  frontal 


Flo.  3.     Left  lateral  view  of  the  skull,  including  mandible,  of  a  specimen  of  Anhinga  anhingn.     Natural  size,  in 
outline,  by  the  author  from  specimen  18259  of  the  Coll.  U.  S.  Nat.  Museum,     sr.m,  the  supramaxillary  bone. 
FIG.  4.    The  same  skull,  seen  from  above.     Mandible  removed. 

region  are  somewhat  narrow  and  elongated ;  the  former  being  smooth  and  moder- 
ately rounded,  the  latter  flat  and  measuring  about  half  a  centimeter  between  the 
sharp  edges  of  the  superior  peripheries  of  the  orbits.  For  its  hinder  half,  longi- 
tudinally, this  part  of  the  skull  presents  a  low,  median  prominence,  created  by  the 
approach  upon  either_side,  of  the  extensive,  though  shallow,  crotaphyte  fossa.  We 


152  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

may  also  see,  upon  this  aspect,  the  conspicuous  exoccipital  processes.  They  project 
almost  directly  backwards,  and  only  slightly  outwards.  Posteriorly,  the  superior 
occipital  area  is  seen  to  be  bounded  above  by  a  sharp  and  raised  line,  much  curved, 
which  distinctly  separates  the  occipital  from  the  parietal  region  of  the  skull.  The 
foramen  magnum  is  very  large,  and  subcircular  in  outline,  its  mid-vertical  diameter 
being  scarcely  shorter  than  its  transverse  one.  The  unnotched  condyle  is  of  good 
size,  hemispherical  in  form,  and  sessile. 

Seen  upon  lateral  aspect,  we  are  struck  with  the  open,  shallow  auditory  fossa, 
which  is  overhung  by  a  raised  squamosal  ridge,  the  squamosal  process  being  small. 
Anterior  to  this  region  the  lateral  wall  of  the  brain  case  is  extensive,  smooth  and 
convex,  otherwise  presenting  no  special  characters.  The  orbits  are  large,  being  con- 
tinuously circular  in  front  and  above,  the  curve  extending  from  the  very  short  post- 
frontal  process  to  the  lower  end  of  the  lacrymal  bone.  No  osseous  septum  divides 
these  cavities,  and  a  large,  median,  heart-shaped  foramen  occupies  the  central  part 
of  the  anterior  wall  of  the  brain-cavity,  from  which,  during  life,  the  olfactory  nerves 
pass  out.  Below  this  another  median  opening  exists,  of  no  inconsiderable  size.  It 
is  the  anterior  common  aperture  of  the  optic  nerves,  and  it  is  flanked  upon  either 
side  by  a  vertical,  scale-like  flake  of  bone,  extending  forwards.  The  parial  grooves 
'for  the  first  pair  of  nerves  faintly  mark  the  orbital  roof  above  ;  each  one  leads  to 
a  corresponding  foramen  found  over  either  pars  piano,  in  front.  A  pars  plana  or 
ethmoidal  wing  is  oblong  in  form,  and  taken  in  connection  with  the  lacrymal,  makes 
a  very  complete  osseous  partition  standing  between  the  eye-socket  and  rhinal  cavity. 
The  mesethmoid  is  small,  and  is  earned  forward  for  a  short  distance  as  a  thin  median 
plate  of  bone,  with  a  free  anterior,  thin  edge.  In  the  forepart  of  the  nasal  cavity 
there  are  two  small  foramina,  in  the  otherwise  solid  wall,  which  lead  forward  into 
the  cancellous  tissue  filling  in  the  upper  osseous  beak.  They  are  placed  side  by  side. 
A  lacrymal  is  a  peculiarly  twisted  bone,  articulating  above  with  the  frontal  and 
nasal.  It  has  an  external  transverse  antero-posterior  deep  groove  above,  below  which 
the  bone  becomes,  as  it  were,  twisted  and  expanded,  into  a  broad  quadrilateral  plate. 
This  stands  transversely  and  forms,  with  the  corresponding  pars  plana,  the  anterior 
orbital  wall.  The  lacrymal  reaches  down  to  the  zygoma  and  is  a  free  bone.  In 
front  it  has,  articulating  with  its  antero-lower  angle,  a  scale-like  piece,  that  stands 
vertically  and  rests  for  its  entire  length  upon  the  upper  surface  of  the  maxillary. 
This  is  the  supra-maxillary.  (Fig.  3  sr.m.)  Each  zygoma  is  twisted  and  much 
flattened.  Anteriorly,  their  broader  surfaces  lie  in  the  horizontal  plane,  while  the 
posterior  moieties  are  in  the  vertical  one.  The  peg-like,  articulatory  nibs  at  their 
hinder  ends  for  the  quadrates  are  very  small.  Looking  at  the  skull  from  a  direct 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  153 

inferior  view,  many  of  the  points  already  described  can  be  distinctly  seen.  This  is 
due  to  the  peculiar  flattened  conformation  of  the  cranium.  Indeed,  the  form  of  the 
brain-case  indicates  that  Anhinga  has  an  elongated,  vertically  compressed  brain,  but 
relatively  not  as  much  so  as  it  is  in  a  Cormorant,  where  it  is  also  wider.  The  basi- 
temporal  area  is  small  and  triangular,  with  moderately  prominent  paroccipital 
processes,  each  one  descending  from  one  of  its  postero-external  angles.  The  anterior 
apex  of  the  basitemporals  is  run  out  as  a  scale-like  point,  which  underlaps  the 
meeting  of  the  thoroughly  open  Eustachian  grooves.  The  usual  foramina  for  the 
facial,  glossopharyngeal,  vagus  and  hypoglossal  nerves,  and  the  internal  carotid 
arteries  are  plainly  seen  in  this  region.  They  are  quite  distinct  from  each  other,  and, 
as  a  rule,  nearly  circular  in  outline.  The  rostrum  of  the  sphenoid  is  a  very  delicate, 
rod-like  bone  that  is  extended  backwards  in  the  median  line  under  the  cranium  as 
far  as  the  eustachian  entrance,  as  a  sharpened  osseous  ridge.  In  front  it  fuses 
with  the  mesethmoid.  For  their  posterior  moieties,  the  palatines  are  thoroughly 
coossified  in  the  middle  line,  where  they  send  down  a  faint  crest  from  the  sutural 
juncture.  As  thus  constituted  the  common  bone  lies  in  the  horizontal  plane,  with 
postero-external  angles  but  faintly  indicated,  but  with  a  short  process  extending 
directly  backwards  from  either  side  of  the  united  facets  for  the  pterygoids.  Anteri- 
orly, the  palatines  are  much  narrower,  where  they  are  also  in  the  horizontal  plane, 
and  mesially  separated  by  an  elongated  opening  that  leads  above  into  the  rhinal 
chamber.  Their  distal  ends  run  forward  to  fuse  with  the  nasals,  maxillaries,  and  pre- 
maxillaries. 

The  maxillo-palatines  are  very  wide  apart,  and  each  one  is  simply  a  subvertical, 
thin,  plate-like  scale  of  bone  for  the  most  part  free  behind,  but  fusing  with  the  usual 
bones  in  front.  A  shallow,  medio-longitudinal  groove  marks  the  united  palatines 
behind,  and  this  is  occupied  by  the  slender,  presphenoidal  rod.  A  quadrate  has  a 
small,  spine-like  orbital  process;  a  compressed  mastoidal  head  of  no  great  size,  which 
is  barely  divided  into  two  facets;  a  large,  antero-posteriorly  disposed  facet  for  the 
mandible  which  is  separated  by  a  pronounced  cleft  from  a  much  smaller  one,  the 
entire  outer  side  of  which  is  occupied  by  the  pit  for  the  end  of  the  zygoma.  The 
bone  I  believe  to  be  pneumatic. 

The  pterygoids  are  flake-like,  flattened  bones  with  very  sharp  edges,  and  with 
very  distinct  ends  bearing  the  articular  facettes  for  the  bones  with  which  they  artic- 
ulate. Each  pterygoid  has  a  length  of  a  little  more  than  a  centimeter.  A  circlet 
of  small  "sclerotal  plates"  are  found  in  either  eye,  and  the  hyoidean  apparatus  is  but 
feebly  developed.  I  have  not  examined  the  ossicles  of  the  ear.  Oonforrning  to  the 
shape  of  the  cranium  and  superior  mandible,  we  find  the  lower  jaw  assumes  the  form 


154  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

of  a  long  and  narrow  V.  The  ramal  sides  are  not  deep ;  there  is  no  ramal  vacuity ; 
and  the  bone  gradually  tapers  to  a  sharp  point  in  front.  From  the  nature  of  the 
splenio-dentary  articulation — the  thin  bones  being  feebly  wedged  together  there  — 
the  mandible  is  of  a  consequence  very  weak  at  that  point.  A  considerable  symphysis 
exists,  with  the  barest  rudiment  of  a  median,  inter-ramal  spine  present.  For  the 
most  part,  the  upper  and  lower  borders  of  the  bone  are  rounded,  though  the  supero- 
dentary  edges,  from  sphenial  articulation  to  apex  are  inclined  to  be  cultrate.  Either 
coronoid  process  is  very  much  reduced,  while  between  it  and  the  articular  cup  for  the 
quadrate,  on  the  mesial  aspect  of  the  ramus,  is  a  long  foramen  of  an  ellipsoidal 
outline,  entering  the  inner  structure  of  the  jaw.  Each  hinder  end  of  the  mandible 
is,  as  usual,  constructed  to  articulate  with  a  corresponding  quadrate.  On  the  upper 
side  of  one  there  is  a  deep,  rather  narrow,  obliquely-placed  cup — its  mesial  end 
being  the  anterior  one.  This  is  for  the  inner  articular  facet  of  the  foot  of  the  quad- 
rate. In  front  of  this  is  a  small,  nearly  flat,  articular  surface,  and  it  is  for  the  outer 
facet  of  the  quadratal  foot.  Facing  directly  forward,  and  standing  on  the  postero- 
internal  edge  of  the  cup  is  still  another  small  facet,  intended  for  a  corresponding 
one  on  the  same  bone.  These  articular  cups  develop  no  inturned  mesial  pro- 
cesses, but  the  usual  pneumatic  foramen  is  present.  The  articular  processes  standing 
out  behind,  are  of  good  size,  of  a  quadrilateral  form,  and  so  twisted  that  the  lateral 
surface  in  either  case  looks  slightly  upward  and,  to  a  much  greater  degree,  outward. 

Of  the  Axial  Skeleton.  —  Endowed  as  it  is  with  special  points  of  interest,  much  has 
been  written  upon  this  part  of  the  anatomy  of  Anhinga.  It  has  been  touched  upon 
with  greater  or  less  elaboration  by  Brandt  (Mem.  de  1'Acad.  Imp.  Sci.  de  St.  Peters- 
bourg,  torn,  v.,  6ime  Serie,  Sect,  de  Sc.  Nat.,  1839),  by  Mivart,  in  his  memoir  in  the 
T.  Z.  S.,  already  cited,  by  Garrod  (Coll.  Sci.  Mem.,  p.  334),  by  Donitz  (Archiv  fur 
Anat.  u.  Phys.,  1873,  p.  357),  and  by  Hunter  (Essays  and  Obser.,  1861,  v.  11,  p. 
328),  and  by  others.  Most  of  these  writers  have  been  attracted  by  the  peculiarities 
seen  in  the  spinal  column,  which  I  will  now  proceed  to  examine. 

In  the  atlas  we  find  the  articular  cup  of  the  condyle  perforated  near  its  upper 
border.  Its  neural  arch  is  nearly  as  deep  as  it  is  wide,  and  from  it  projects  behind, 
upon  either  side,  a  conspicuous  little  spine.  The  small  hyapophysis  of  this  vertebra 
also  projects  posteriorly  beyond  the  centrum.  From  the  axis  to  the  seventh  inclu- 
sive, the  vertebrae  are  especially  notable  for  being  of  no  great  caliber  in  point  of  size, 
and  at  the  same  time  remarkably  elongated.  A  low,  sharp  neural  ridge  and  hyapo- 
physial  spine  characterize  the  axis.  Its  postzygapophysial  part  is  welded  into  a 
common  plate  of  bone,  with  the  articular  facets  upon  its  under  side.  Upon  its 
ventro-posterior  aspect  an  open  channel  is  formed  by  a  curling  downwards  of  bone 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  155 

from  the  centrum  upon  either  side.  This  traverses  the  entire  length  of  the  verte- 
bral body  in  the  third,  fourth,  fifth,  sixth,  and  seventh  vertebne,  but  becomes  less 
and  less  marked.  On  the  eighth  it  is  strong  again,  running  between  the  enor- 
mously long  parapophysial  processes.  In  the  ninth  it  is  the  subvertebral  arterial 
channel,  and  is  arched  over  with  bone  anteriorly.  This  remains  to  be  the  case  to 
the  thirteenth  inclusive,  while  in  the  fourteenth  the  channel  disappears  behind, 
though  the  covered  arterial  passage  still  persists  on  the  antero-ventral  aspect,  beneath 
the  centrum.  Both  are  absent  in  the  fifteenth  vertebra.  Parial  parapophysial  spines 
first  appear  in  the  axis,  where  their  distal  apices  fuse  with  the  bone  posteriorly. 
These  spines,  though  present,  are  by  no  means  a  prominent  character  in  the  third  to 
the  seventh  vertebra  inclusive.  Suddenly  in  the  eighth  they  become  remarkably 
developed,  and  are  nearly  as  long  as  the  bone  itself.  In  the  ninth  they  at  once 
commence  to  shorten  again,  and  this  rapidly  continues  to  be  the  case,  until  they, 
after  somewhat  changing  their  character,  have  entirely  disappeared  in  the  seven- 
teenth vertebra.  A  most  remarkable  series  of  "lateral  canals"  exist  in  these 
vertebrae.  I  note  them  first  in  the  axis,  where  they  are  of  capillary  dimensions 
and  run  nearly  the  entire  length  of  that  elongated  bone.  Anteriorly,  either  one 
opens  at  the  base  of  the  odontoid  process,  the  posterior  opening  being  on  the  side 
of  the  vertebra  near  the  postzygapophysial  base.  In  the  third  vertebra  these  canals 
are  almost  imperceptibly  increased  in  caliber,  and  open  upon  either  side,  anteriorly, 
in  a  slit  which  is  seen  to  exist  between  the  prezygapophysial  facet  and  the  very 
much  vertically  compressed  facet  of  the  centrum.  Behind,  it  opens  a  couple  of 
millimeters  in  front  of  the  articular  surface  of  the  centrum.  But  little  change 
takes  place  in  this  particular  in  the  fourth  to  the  seventh  vertebra  inclusive,  except 
that  in  the  fifth,  sixth  and  seventh  a  minute  foraminal  opening  pierces  the  canal  on 
either  side  about  the  middle  of  the  bone  on  its  ventral  aspect.  In  the  eighth 
vertebra  the  caliber  of  the  lateral  canals  is  about  doubled  and  their  posterior  open- 
ings are  moved  far  forwards  so  as  to  be  found  on  the  side  of  the  vertebra,  above  the 
base  of  the  enormously  elongated  parapophysial  process  ;  and  between  two  fringe- 
like,  long,  ossified  tendons  that  are  attached  to  and  especially  characterize  this 
bone  of  the  vertebral  chain.  With  their  anterior  openings  remaining  practically 
the  same  as  described  above,  and  the  hinder  ones  just  posterior  to  the  parapophyses, 
no  change  is  noted  in  the  ninth  except  an  increase  in  point  of  the  size  of  the  tube 
on  either  side.  This  increase  goes  on  gradually  to  include  the  eighteenth  vertebra, 
in  which  bone  these  lateral  canals  last  appear.  In  the  seventeenth  they  are  very 
short,  truly  lateral,  and  somewhat  compressed  from  above  downwards ;  markedly 
most  compressed  in  the  eighteenth. 


156  MEMOIRS    OF    THE    CARNEGIE    MUSEUM 

The  neural  spine,  feebly  developed  in  the  third  vertebra,  becomes  a  prominent 
character  of  the  fourth,  where  it  occupies  the  posterior  moiety  of  the  bone,  as  a  con- 
spicuous blade-like  crest,  with  rounded  superior  margin.  In  the  fifth,  sixth,  and 
seventh  this  character  disappears ;  in  the  eighth  it  is  feebly  present ;  in  the  ninth  it 
is  a  roughened  tubercle,  entirely  vanishing  again  in  the  tenth  to  the  fifteenth 
inclusive.  In  the  remainder  of  the  series,  back  as  far  as  the  pelvis,  it  is  large 
and  of  an  oblong  form,  with  thickened  superior  border.  Throughout  the  dor- 
sal vertebrae,  ossified  tendons  of  great  length  are  coossified  with  this  spine,  pro- 
jecting backward  in  the  leading  dorsals,  and  both  backward  and  forward  in  the 
ultimate  ones. 

A  low,  sharp,  haemal  spine  occurs  on  the  ninth  vertebra ;  it  being  at  the  anterior 
part  of  the  bone,  on  the  parapophysial  bridge  that  closes  in  the  passage  for  the 
carotids.  It  is  still  better  developed  on  the  tenth  ;  where  sharp  lateral  ridges  begin 
to  show,  one  upon  either  side  of  it.  All  these  processes  are  very  pronounced  in  the 
thirteenth  and  fourteenth,  while  in  the  fifteenth  their  entire  character  is  changed. 
In  it  the  lateral  ridges  almost  entirely  disappear,  and  an  enormous,  quadrate  haemal 
spine  is  thrown  down  from  nearly  the  entire  length  of  the  centrum.  In  the  sixteenth 
it  is  not  quite  so  large,  and  its  hinder  angle  is  produced  backwards.  A  remarkable 
change  is  seen  in  the  seventeenth  vertebra,  where  the  ventral  aspect  of  the  centrum 
is  very  much  broadened,  quite  flat,  and  the  little  hook-like,  laterally-compressed 
hsemal  spine  occupies  a  mid-position  on  the  posterior  border.  In  the  eighteenth, 
ninteenth  and  twentieth  the  process  is  practically  absent,  and  the  great  breadth  of 
the  centrum  gradually  narrows  again,  as  its  lateral  margins  are  deflected.  This  form 
sees  its  extreme  in  the  twenty-first  vertebra,  where  the  centrum  is  markedly  com- 
pressed from  side  to  side,  and  the  aforesaid  lateral  margins  are,  ventrally,  converted 
into  a  double  haemal  spine. 

In  the  twenty-second  and  twenty-third  the  spine  is  single,  and  the  transverse 
compression  of  the  centra  is  most  apparent,  being  present  in  a  marked  degree. 

Anapophysial  ridges  are  more  or  less  conspicuously  developed  in  the  ninth  to 
the  fourteenth  vertebrae,  inclusive,  and  in  the  dorsal  series  proper,  are  long  and 
broad,  and,  as  said  above,  are 'provided  with  fringe-like  metapophyses  frequently  of 
considerable  length. 

In  the  first  eight  cervicals,  the  anterior  articular  facets  are  placed  laterally  upon 
either  side  of  the  neural  canal,  and  their  surfaces  face  forwards  and  towards  the 
median  plane.  In  the  ninth  vertebra  these  facets  are,  as  it  were,  rotated  backwards, 
so  as  to  be  above  the  neural  canal,  and  face  towards  the  median  plane,  and  very 
slightly  dorsad. 


SHUFKLDT  :     OSTEOLOGY    OF   THE    STEGANOPODES  157 

So  in  the  articulation  of  the  eighth  vertebra  with  the  ninth,  a  decided  angle  is 
made — nearly  a  right  angle — with  its  salient  point  to  the  front.  This  also  occurs 
between  the  ninth  and  the  tenth  and  so  on  down  the  chain,  becoming,  however,  less 
and  less  marked,  disappearing  entirely  after  the  fifteenth,  after  which  the  vertebrae 
articulate  in  a  straight  line.  The  extremities  of  the  long  parapophysial  processes  of 
the  eighth  vertebra?  articulate  in  the  shallow  grooves  on  the  forepart  of  the  ninth 
vertebra,  on  its  ventral  aspect. 

Garrod  has  said  that  "Donitz  figures  a  pair  of  accessory  bony  bridges  on  the 
dorsal  surface  of  the  vertebra  following  the  most  lengthy  one,  which  must  evidently, 
therefore,  be  the  ninth.  He,  however,  speaks  of  it  as  the  eighth,  which  seems  to  me 
to  be  an  error  depending  on  the  omission  of  the  consideration  of  the  atlas,  because 
in  Plotus  anhinga  (both  from  Brandt's  figure  and  my  specimens)  it  is  most  certainly 
the  ninth,  as  it  is  in  Plotus  novse-hollandias,  Pkalacrocomx  carbo,  and  P.  lugubris.  I 
have,  however,  not  seen  Plotus  levaillantii." 

"Donitz  attributed  the  peculiar  kink  of  the  neck  of  the  Darters,  which  it  is 
impossible  to  obliterate  without  lacerating  the  surrounding  muscles,  to  the  presence 
of  the  bony  bridges  he  describes;  in  this,  however,  he  is  mistaken,  it  depending  on 
the  above-mentioned  peculiarity  in  the  eighth  cervical  vertebra,  by  which  it  is  angu- 
larly articulated  with  the  seventh  and  ninth  vertebrae,  the  upper  genu  being  posterior, 
and  the  lower  anterior.  In  further  verification  of  this,  it  may  be  stated  that  in 
P.  anhinga  the  bony  bridges  do  not  exist,  and  yet  the  kinking  is  most  strongly 
marked."  (Coll.  Scientif.  Mem.,  pp.  336,  337.)  The  bridges  here  spoken  of  are  also 
absent  in  my  specimen  of  A.  anhinga. 

The  neural  tube  is  not  very  large  in  the  first  eight  cervicals,  where  it  has  more 
or  less  a  cylindrical  form  posteriorly,  but  becomes  somewhat  antero-posteriorly  com- 
pressed as  we  gradually  pass  towards  the  fore  end  of  the  vertebra.  Increasing  again 
in  size  after  the  ninth,  it  seems  to  attain  its  greatest  capacity  in  the  sixteenth,  seven- 
teenth and  eighteenth,  to  become  small  and  cylindrical  once  more  as  it  passes  through 
the  dorsal  series.  In  the  ninth  and  tenth  vertebra?  the  anterior  opening  of  the  neural 
canal  lies  in  a  plane  which  is  about  perpendicular,  in  each  case,  to  the  plane  in  which 
the  posterior  opening  is  found.  That  is,  upon  direct  dorsal  view  of  either  of  these 
two  vertebra?,  the  posterior  opening  of  the  neural  canal  is  not  in  sight,  while  we  look 
almost  directly  into  the  anterior  opening. 

On  the  sixteenth  vertebra  we  find  the  first  pair  of  cervical  ribs ;  they  are  long 
and  slender  and  without  uniform  processes.  We  find  also  a  large  pair  of  free  ribs 
on  the  seventeenth  cervical  vertebra,  which  commonly  have  unciform  appendages. 
These  are  anchylosed  to  the  bone,  and  are  large  and  broad.  Next  to  these  two  pairs 


158  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

of  cervical  ribs,  we  meet  with  three  pairs  of  true  dorsal  ones,  they  all  having  large 
costal  processes,  and  all  joining  with  the  sternum  by  means  of  their  haemapophyses. 
There  are  two  pairs  of  pelvic  ribs,  the  first  having  stunted  costal  processes,  though 
its  haemapophyses  join  with  the  sternum.  In  the  last  pair  the  unciform  appendages 
are  always  entirely  absent,  and  the  costal  ribs  do  not  reach  the  sternum.  Briefly 
then,  there  are  seven  pairs  of  ribs  in  this  Darter,  and  this  I  believe  to  be  generally 
the  arrangement  in  all  typical  Cormorants. 

Several  of  the  authorities  I  have  referred  to  above  have  both  described  and  fig- 
ured the  pelvis  of  an  Anhinga,  and  the  bone  possesses  a  number  of  interesting  char- 
acters. Fifteen  vertebrae  of  the  spinal  column  fuse  together  to  form  its  "  sacrum." 
The  leading  six  of  these  throw  out  their  transverse  processes  to  coossify  with  the  ven- 
tral surfaces  of  the  anterior  portions  of  the  ilia.  The  centra  of  the  first  three  are 
markedly  compressed  transversely,  the  first  one  being  very  deep,  the  next  less  so, 
still  less  so  the  last.  A  large  haemal  spine  is  also  found  on  the  first,  which  becomes 
rudimentary  on  the  one  behind,  to  be  entirely  absent  in  the  one  next  in  order. 
Two  or  three  vertebrae  throw  out  their  processes  to  abut,  upon  either  side,  against 
the  ilia  at  points  just  posterior  to  the  cotyloid  rings.  Posterior  to  these,  the  outer 
extremities  of  the  processes  of  the  vertebrae  completely  fuse  with  the  inner  borders 
of  the  ilia ;  while  on  either  side,  from  the  acetabulae  all  the  way  to  the  tail,  occurs  a 
row  of  interapophysial  foramina,  a  feature  so  characteristic  of  the  pelves  of  the  Cor- 
morants. The  last  vertebra,  though  not  free,  is  to  some  extent  individualized,  and 
the  extremities  of  its  transverse  processes  may  not  so  completely  ossify  with  the 
ilium  on  either  hand,  which  latter  bones  are  here  drawn  out  into  peculiarly  elon- 
gated posterior  processes.  Viewed  upon  its  dorsal  aspect  we  are  to  note  that  the  an- 
terior portions  of  the  ilia  are  much  horizontally  expanded,  while  the  narrowest  part 
of  the  pelvis  is  just  in  front  of  the  acetabulae,  where  either  iliac  border  shows  a 
marked  concavity.  Thorough  fusion  of  the  internal  iliac  borders  and  the  "  sacral 
crista"  takes  place,  and  not  even  do  the  usual  "  neural  canals  "  or  "grooves"  remain 
open  posteriorly.  This  is  well  shown  in  Plotus  levaillanti  (PI.  XXL,  Fig.  1).  In 
front  the  iliac  borders  develop  a  raised  emargination,  and  a  strong  brush  of  coossified 
tendons  always  project  directly  forward  from  the  diapophyses  and  neural  spine  of 
the  leading  vertebra  of  the  "  sacrum."  Passing  to  the  post-acetabular  portion  we  find 
that  the  pelvis  is  broader  than  it  is  in  some  of  the  Cormorants,  and  we  are  particu- 
larly struck  with  the  prominent  crests  formed  by  the  union  of  the  internal  iliac 
borders  and  the  sacrum.  The  neural  arch  and  the  common  neural  spine  of  the  lat- 
ter is  also  conspicuously  raised  in  this  part  of  the  pelvis.  This  begins  moderately 
about  opposite  the  cotyloid  rings,  and  increases  as  we  advance  towards  the  tail. 


SHUFELDT  :     OSTEOLOGY    OF   THE    STEGANOPODES  159 

This  elevation  of  the  center  and  margins  causes  the  formation  of  longitudinal  de- 
pressions between  them,  and  down  the  center  of  either  one  of  these  we  find  the  row 
of  interapophysial  foramina,  to  which  reference  has  already  been  made  above. 

Some  Cormorants  seem  to  have  a  fairly  well  marked  propubic  spine,  and  there  is 
an  indication  of  the  rudiment  of  such  a  process  in  the  Anhinga.  The  internal  cir- 
cumference of  either  cotyloid  ring  is  smaller  than  the  external,  and  these  cavities 
are  brought  up  very  close  to  the  sacrum.  Of  enormous  dimensions  is  the  ischiadic 
foramen ;  it  has  the  effect  of  absorbing  nearly  all  the  ilium  above,  and  to  some  ex- 
tent behind  it;  while  below,  it  makes  the  neck  of  the  ischium  very  narrow  indeed. 
Inform  this  large  foramen  is  subelliptical.  The  "obturator  foramen"  opens  into 
the  obturator  space,  which  latter  is  also  extensive,  and  the  pubic  style  which  bounds 
it  below  as  far  as  the  point  where  it  meets  the  ischium,  is  very  slender  and  frail. 
Beyond  this,  the  pubic  bone  is  in  close  contact  with  the  lower  margin  of  the 
ischium,  where  it  is  very  considerably  stouter,  as  it.  also  is  after  it  becomes  suddenly 
deflected  behind  after  passing  the  extreme  distal  angle  of  the  ischium  —  precisely  as 
as  it  does  in  typical  Cormorants. 

A  deep,  triangular  ilio-ischiadic  notch,  between  the  here  very  narrow  ilium  and 
the  far  broader  ischium,  indents  the  posterior  pelvic  border. 

The  'antitrochanters  are  prominent,  and  the  facet  on  either  one  of  them  looks 
forwards,  downwards  and  slightly  outwards. 

Ventrally,  the  "pelvic  basin"  is  seen  to  be  fairly  capacious;  the  "sacrum"  is  con- 
siderably enlarged  opposite  the  acetabulse  and  beyond  ;  the  exits  for  the  nerves  of 
the  sacral  plexus  are  double ;  finally,  in  front,  we  see  the  horizontally  spreading 
ilia,  with  the  compressed  vertebrae,  dipping  down  anteriorly  so  far  ventrad. 

There  are  six  free  caudal  vertebrae  in  the  skeleton  of  the  tail  of  this  Darter, 
plus  a  large  pygostyle.  This  latter  bone  is  drawn  out  supero-posteriorly,  and  the 
long  superior  edge  is  very  sharp.  Its  antero-inferior  angle  is  enlarged,  with  flattened 
surface  below.  Beyond  this,  the  inferior  border  gradually  contracts  and  becomes 
rounded.  In  front  there  is  an  extensive  pit  for  articulation  with  the  last  caudal 
vertebra,  and  above  this  there  is  a  small  opening  where  the  spinal  cord  enters 
this  bone. 

The  centra  and  their  articulatory  facets  are  large  in  these  vertebrae,  but  the 
spinal  canal  is  of  no  great  caliber.  In  mid-series  the  neural  arch  and  spine,  and 
the  forward-projecting  prezygapophyscs  are  conspicuous.  A  good-sized  haemal  spine 
also  characterizes  the  last  four  vertebra,  and  in  each  case  it  extends  forwards  to 
underlap  the  bone  next  in  advance.  As  a  rule  the  transverse  processes  are  rather 
short  and  stumpy,  being  entirely  rudimentary  in  the  sixth  caudal. 


160 


MEMOIRS    OF    THE    CARNEGIE    MUSEUM 


FIG.  5.  Ventral  aspect  of  the  sternum  of  Anhinga  anlringa. 

FlO.  6.  Left  lateral  view  of  the  same  bone  shown  in  Fig.  5. 

FIG.  7.  Anterior  aspect  of  the  osftircula  of  Anhinga  anliinga. 

Flo.  8.  Mesial  side  of  the  scapular  end  of  the  same  bone  shown 
in  Fig.  7.  All  the  cuts  are  natural  size  from  the  specimen  (No. 
18259,  Colls.  U.  S.  Nat.  Mus.).  Outline  drawings  by  the  author. 


The  Sternum  and  Shoulder 
Girdle.  —  Many  of  the  characters 
of  the  sternum  of  a  Darter  es- 
sentially agree  with  the  corre- 
sponding ones  as  they  occur  in 
the  sternum  of  such  Cormorants 
as  represent  the  genus  Phalacro- 
corax.  Its  carina  dies  out  on  the 
under  surface  of  the  body  before 
arriving  at  the  mid-xiphoidal 
process  behind ;  and  is  deep  only 
in  front,  where  it  protrudes  for-  . 
wards,  with  a  sharp  anterior  bor- 
der, and  bears  a  large  facet,  oc- 
cupying the  carinal  angle,  for 
articulation  with  the  os  furcula. 
Only  the  merest  rudiment  of  a 
manubrium  is  to  be  seen  at  the 
usual  site ;  possibly  the  process 
is  entirely  absent  in  some  speci- 
mens. A  wide  concave  notch 
separates  the  coracoidal  grooves 
mesiad,  and  the  large,  elongated 
coracoidal  facets  above  them. 
Large,  acutely  triangular  costal 
processes  are  developed,  each  one 
projecting  outwards  at  an  angle 
of  about  45°,  and  very  slight 
forwards.  The  costal  borders 
are  short  and  much  contracted  ; 
either  one  supports  four  trans- 
verse hsemapophysial  facets. 
Posterior  to  the  costal  borders  the 
sternum  widens,  and  its  lateral 
margins  are  sharp.  Its  hinder 
border  is  also  sharp.  Two  large, 
broadly  concave  notches  exist 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  161 

here.  They  give  rise  to  long,  lateral  xiphoidal  processes,  and  a  shorter  mid-xiphoidal 
process.  On  its  thoracic  aspect  the  sternal  body  as  a  whole  is  well  concaved — uni- 
formly so,  as  the  position  of  the  heel  beneath  is  but  barely  indicated  down  the 
median  line.  The  form  and  proportions  of  the  sternum  in  Anhinga  are  well  shown 
in  my  figures  5  and  6. 

The  osfurculais  of  the  typical  U-shaped  pattern,  with  large,  expanded  clavicular 
heads.  There  is  but  the  barest  rudiment  of  a  hypocleidium  below,  while  a  facet  is 
present  on  the  nether  side  of  it,  for  articulation  with  the  carinal  angle  of  the  keel  of 
the  sternum.  Either  broad,  laterally-compressed  clavicular  head,  is  bent  rather 
abruptly  downwards ;  a  projecting,  facet-bearing  shoulder  is  developed  for  the  coracoi- 
dal  articulation.  Above  either  of  these  facets  we  note  a  strong  process  pointing  back- 
wards, which,  when  the  os  furcula  is  articulated  in  situ,  rests  upon  the  summit  of 
the  corresponding  coracoid.  (See  Figs.  7  and  8.) 

Both  Darters  and  Cormorants  have  unusually  long  coracoids.  In  Anhinga  the 
coracoid  is  longer  than  the  femur.  Its  sternal  end  is  considerably  expanded,  and 
shows  a  wide  and  rather  deep  excavation  on  its  posterior  aspect  for  the  coracoidal 
groove  and  facet  upon  the  sternum,  while  anteriorly  the  corresponding  surface  is 
narrow  and  shallow.  A  costal  process  is  not  developed,  but  that  border  is  convexly 
rounded  and  sharp.  The  shaft  of  this  bone  is  antero-posteriorly  much  compressed, 
and  in  front  a  strong,  muscular  line  marks  it  longitudinally,  especially  near  the 
sternal  end.  The  scapular  process  is  much  aborted,  but  the  head  is  quite  massive  and 
tuberous.  Its  entire  antero-mesial  aspect  is  occupied  by  an  oval  facet  for  articula- 
tion with  the  clavicular  head  of  the  furcula.  The  scapular  facet  is  small,  but  the 
glenoid  surface  is  of  fair  size. 

Quite  uniform  in  width  and  moderately  pointed  distally,  the  thickish  blade  of  a 
scapula  has  its  posterior  extremity  but  very  slightly  bent  outwards.  The  anterior 
end  of  this  bone  is  wide  transversely,  and  the  long  acromial  process  decidedly 
tilted  up.  The  glenoidal  process  also  stands  out  rather  prominently,  while  the 
articular  facet  for  the  coracoid  is  comparatively  small.  Just  posterior  and  beyond 
the  glenoidal  facet,  the  border  of  the  scapula  is  broadly  rounded,  but  is  sharp  all 
along  its  mesial  edge,  clear  to  the  tip  of  the  acromial  process.  It  is  only  the  distal 
third  of  the  bone  that  is  vertically  compressed  and  at  all  blade-like. 

On  the  Appendicular  Skeleton. 

Being  thoroughly  non-pneumatic,  the  long  bones  of  the  limbs  in  Anhinga  are 
solid  and  heavy.  Although  not  so  very  far  from  being  double  the  size,  the  humerus 
of  Fregata  weighs  about  the  same  as  the  humerus  of  the  species  of  Darter  we  are  now 


162 


MEMOIRS    OF    THE    CARNEGIE    MUSEUM 


describing.  In  PJialacrocorax  urile  the  ulna  is  somewhat  longer  than  the  humerus, 
while  in  this  Darter  the  humerus  is  considerably  longer  than  the  ulna.  These  are 
interesting  facts. 

In  Anhinga  anhinga  the  humerus  has  a  length  of  about  13  centimeters,  and  it 
presents  the  usual  double  sigmoid  curve.     This  latter,  however,  is  far  better  seen  upon 

a  superior  view  of  the  bone,  rather  than  upon  its 
anconal  aspect.     (See  Fig.  9.) 

The  proximal  end  of  the  bone  is  narrow  and 
elongated,  merging  with  the  shaft  very  gradually. 
The  radial  crest  is  a  low,  long  ridge  of  uniform 
height ;  while  the  ulnar  crest  and  tuberosity  are 
prominent  and  are  bent  anconad.  This  creates  a 
deep  valley  between  the  true  articular  humeral 
head  and  the  ulnar  protuberance.  The  excavation 
over  which  the  latter  arches,  and  where  the  pneu- 
matic openings  usually  occur  in  other  birds,  is  very 
shallow,  and  indeed  so  very  much  so  that  really  no 
fossa  may  be  said  to  exist  there  at  all.  A  marked 
diffuse  excavation  exists  upon  the  palmar  aspect 
of  this  part  of  the  humerus ;  this  is  spread  out 
over  a  regular  area  just  within  the  distal  half  of  the 
radial  crest,  but  joins  with  a  far  narrower  and  some- 
what deeper  strip  that  bounds  the  humeral  head 
distad,  and  lies  on  the  opposite  side  of  the  bone 
to  the  ulnar  crest.  All  this  excavation  is  power- 
fully marked  in  PJialacrocorax. 

The  humeral  shaft  proper  is  subcylindrical  in 
form,  being  of  nearly  uniform  caliber  for  the 
middle  third  of  the  bone.  At  the  distal  extremity 
all  the  most  usual  ornithic  characters  are  promi- 
nent and  pronounced.  The  olecranon  fossa  is 
shallow,  but  the  ulnar  and  radial  tubercles  jut  out 
very  conspicuously,  though  not  as  markedly  so  in 
proportion  as  in  the  Cormorants. 

The  ulna  has  a  length  of  about  11.5  cm.  and  is 
moderately  bowed  from  one  end  to  the  other.  The  points  of  attachments  for  the 
quill-butts  of  the  secondary  feathers  present  quite  a  striking  feature,  and  each  seems 


Fia.  9.  Anconal  aspect  of  right  hu- 
merus of  Anhinga  anhinga.  FIG.  10.  An- 
terior view  of  right  femur  of  A.  anhinga. 
Fia.  11.  Right  coracoid  of  A.  anhinga. 
Seen  from  in  front.  All  drawn  in  outline, 
natural  size,  by  the  author,  from  Spec.  No. 
18259,  Coll.  of  U.  S.  Nat.  Museum. 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  1 63 

to  consist  in  a  small  pitlet,  with  its  upper  and  lower  edges  very  slightly  raised,  but 
in  a  manner  hardly  to  suggest  the  idea  of  a  "papilla"  or  "  tubercle"  as  I  have  so 
frequently  described  them  for  many  other  kinds  of  birds. 

The  ulna  develops  a  distinct  lip  of  bone,  that  curves  partly  round  the  head  of 
the  radius  when  they  are  articulated  in  situ.  This  latter  bone,  hardly  half  the  cali- 
ber of  the  ulna,  shows  barely  any  bowing  or  curving  at  all  throughout  its  contin- 
uity. Distally  it  is  deeply  grooved  on  top  for  the  passage  of  tendons,  while  a  deep 
circular  cup  for  articulation  with  the  radial  tubercle  on  the  humerus  surmounts  its 
head  or  proximal  extremity. 

The  two  usual  ossicles,  radiate  and  ulnare,  compose  the  skeleton  of  the  wrist  in 
the  adult. 

The  carpo-metacarpus  has  a  total  length  of  6.5  cm.  and  is  characterized  princi- 
pally by  a  deep  pit  on  the  palmar  size  of  the  head,  between  the  pollex  metacarpal 
and  the  process  for  muscular  attachment.  This  is  also  a  very  general  phalacrocora- 
cine  character.  The  shafts  of  index  and  medius  metacarpals  are  very  straight,  and 
the  latter  about  as  long  as  the  former,  has  not  more  than  about  one  fourth  its  bulk, 
and  is  compressed  throughout,  the  flat  surface  of  the  opposed  side  being  presented 
to  the  shaft  of  the  former.  The  pollex  metacarpal  is  short,  and,  on  the  whole  the 
bone  is  not  very  unlike  what  we  find  it  to  be  in  the  Cormorants. 

No  perforation  exists  in  the  dorsal  expansion  of  the  proximal  phalanx  of  the 
index  digit,  and  none  of  the  terminal  joints  of  either  the  thumb  or  the  other  two 
fingers  have  claws  at  their  extremities.  The  one  belonging  to  the  medius  is  com- 
paratively long,  and  very  sharply  pointed. 

I  am  not  familiar  with  the  existence  of  any  special  sesamoids  about  the  articu- 
lations in  the  skeleton  of  the  anterior  extremity,  at  places  where  they  exist  in  some 
Auks  and  other  water  birds. 

Passing  to  the  PELVIC  LIMB  we  find  a  femur  with  a  length  of  5.5  cm.;  a  tibio- 
tarsus  with  a  length  of  9  cm.;  a  tarso-metatarsus  of  4  cm.;  an  accessory  metatarsus 
of  1.4  cm.,  which  is  nearly  equalled  by  the  patella  —  it  having  a  length  of  1.2  cm. 
In  the  foot,  the  skeleton  of  hallux  measures  3.1  cm.,  the  inside  toe  4.7  cm.,  mid- 
dle toe  7.5  cm.,  and  outside  toe  8  cm. — the  ungual  joints  being  included  in  each 
case. 

Proportionately  the  femur  is  longer  in  Anhinga  than  it  is  in  P.  urile,  and  is  not 
bowed  so  much  in  the  antero-posterior  direction.  The  summit  of  the  bone  is  capped 
off  with  the  articular  surface,  above  which  neither  the  caput  femoris  nor  the  trochan- 
terian  crest,  rises.  The  external  condyle  is  more  prominent  and  lower  on  the  bone 
than  the  internal  one,  and  is  deeply  cleft  for  articulation  with  the  head  of  the  fibula. 


]64  MEMOIRS    OF   THE   CARNEGIE    MUSEUM 

Neither  the  "rotular  channel,"  nor  the  popliteal  fossa  are  very  deeply  excavated  ; 
and  on  the  head  of  the  bone  the  pitlet  for  the  ligamentum  teres  is  also  quite  shallow. 
The  muscular  lines  of  the  shaft  are  distinctly  denned  both  in  front  and  behind. 

With  its  shaft  somewhat  antero-posteriorly  compressed,  and  very  slightly  bowed 
to  the  front,  the  tibia-tarsus'  presents  us  with  pro-  and  ectocnemial  processes  well 
developed,  and  a  cnemial  crest  that  rises  above  the  summit  of  the  bone.  Of  con- 
siderable length  is  the  conspicuous  ridge  for  articulation  with  the  fibula,  and  at  the 
antero-distal  extremity  of  the  shaft  we  observe  the  presence  of  the  osseous  bridge 
under  which  the  tendons  pass  in  life.  This  end  of  the  bone  inclines  as  it  were  to 
the  inner  side,  so  that  if  the  mid-vertical  axis  of  the  large  internal  condyle  were 
extended  it  would  be  removed  from  and  parallel  to,  the  longitudinal  axis  of  the 
shaft,  rather  than  being  in  the  same  line  with  it. 

Both  extremities  of  this  bone,  as  is  the  case  with  the  extremities  of  the  tarso- 
metatarsus,  are  more  or  less  massive  and  enlarged  as  compared  with  the  shafts  of 
the  same.  Coming  to  the  fibula,  it  is  very  interesting  from  the  fact  that  it  is  com- 
plete, rather  more  so  if  anything  than  we  find  it  to  be  in  either  Pandion  or  Urinator, 
and  is  only  anchylosed  to  the  tibio-tarsus  by  means  of  its  enlarged  and  extreme 
distal  end.  This  limited  fusion  of  the  two  bones  takes  place  at  a  point  just  above 
the  external  condyle. 

Anhinga  has  a  large  patella,  but  proportionately  not  as  large  as  we  find  it  in  the 
Cormorants.  It  is  an  oblong  sesamoid,  nearly  equilateral,  concave  behind  and 
convex  anteriorly,  where  it  is  transversely  perforated  by  a  minute  foramen  for  the 
passage  of  the  ambiens  muscle. 

As  will  be  seen  from  measurements  above,  the  tarso-metatarsios  is  relatively  a  short 
bone  of  the  leg;  it  is  further  characterized  by  having  its  somewhat  broad  shaft  com- 
pressed in  the  antero-posterior  direction  and  marked  longitudinally  upon  both 
aspects  by  strong  muscular  and  tendinal  lines  and  grooves.  The  hypotarsus  is 
strongly  developed,  especially  the  interno-lateral  part  of  it,  which,  by  a  plate-like 
extension,  has  a  firm  attachment  to  the  upper  third  of  the  shaft.  Its  posterior  angle 
above  is  always  thickened  and  doubly  pierced  for  tendons.  The  externo-lateral  part 
of  the  hypotarsus  is  small  and  it  also  creates  by  its  form  a  groove  and  a  foramen  for 
certain  tendons  that  pass  through  or  over  them  during  the  life  of  the  individual. 

One  or  two  small  foramina  pierce  the  upper  part  of  the  shaft  in  an  antero-pos- 
terior direction,  the  most  constant  one  making  its  exit  behind  to  the  inner  side  of 
and  at  the  base  of  the  hypotarsus.  At  the  distal  end  the  trochlese  for  the  toes 
stand  well  apart.  The  inner  one  of  the  three  is  the  lowest,  and  juts  out  in  a  prom- 
inent way  from  the  bone,  and  has  a  tubercle  projecting  from  its  lateral  aspect. 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODKS  165 

The  mid-trochlea  is  massive,  not  quite  centrally  located  on  the  end  of  the  shaft, 
and  is  the  next  lowest  in  point  of  position.  The  highest  of  all  is  the  external  one, 
and  its  outer  part  is  produced  the  farther  behind. 

On  the  anterior  part  of  the  shaft  in  front,  in  the  groove  extending  up  from 
between  the  mid-  and  external  trochlere,  occur  two  perforating  foramina.  The  lower 
one  makes  its  exit  in  the  intertrochlear  notch ;  the  other  on  the  shaft  above  it. 
Nearly  all  existing  birds  have  only  a  single  foramen  at  this  point.  It  is  even  single 
in  Phalacrocorax. 

The  free  first  metatarsal  is  large  and  strong,  twisted  upon  itself,  and  with  an  elon- 
gated transverse  facet  for  articulation  with  the  hallux.  The  skeleton  of  the  pes  is 
remarkably  well  developed.  The  phalangeal  joints,  arranged  upon  the  plan  of  2,  3, 
4,  5  for  hallux  to  outer  toe  inclusive,  are  stout  and  strong,  and  the  terminal  ungual 
joints  are,  one  and  all,  handsomely  curved  and  sharply  pointed  at  their  extremities. 

We  now  pass  to  the  consideration  of  the  osteology  of  the  Cormorants,  which  it 
will  be  found  agrees  in  many  particulars  with  the  species  of  Darter  we  have  just 
been  describing. 

Observations  on  tha  Skelefology  of  the  Phalacrocoracidx.10 

A  great  many  Cormorants  of  the  world's  avifauna,  as  I  have  before  stated,  belong 
in  this  family,  and  as  far  as  at  present  known  it  is  the  only  one  represented  in  the 
United  States,  where,  as  heretofore  noted,  the  nearly  a  dozen  species  and  sub- 
species it  contains  have  all  been  restricted  to  the  single  genus  Phalacrocorax.  Cor- 
morants are  a  good  deal  alike  in  their  osteology,  and  in  this  part  of  their  anatomy, 
too,  they  have  a  good  deal  in  common  with  the  Darters.  To  give  the  salient  features 
of  the  skeleton  in  this  group  I  will  draw  upon  the  skeleton  of  P.  urile  in  particular, 
as  well  as  in  general  those  of  the  collections  of  the  U.  S.  National  Museum,  and 
also  republish  a  short  description,  together  with  the  figures  illustrating  it,  of  P.  per- 

10  In  his  recent  ( 1899)  Hand-List  of  Birds,  Dr.  R.  Bowdler  Sharpe  presents  also  a  classification  of  the  Cormorants 
(pp.  232-235).  They  constitute  the  first  group  of  his  Order  (XXIII.)  Pelecaniformes,  and  all  are  relegated  to  the 
family  Pltalacrocorncitlic,  and  this  latter  is  divided  into  four  (4)  genera,  viz:  ( 1 )  PhalacroLOrax ;  (2)  Pallasicarbo ; 
(3)  Nannopterum,  and  (4)  Actiornia.  The  first  of  these  contains  forty-two  (42)  species  of  existing  cormorants,  and  ten 
(10)  extinct  forms  ;  the  second  is  represented  by  a  single  extinct  type,  the  P.  perspicillatus ;  the  third  contains  only  the 
singular  cormorant  of  Narborough  and  the  Galapagos  Islands  ;  while  finally,  the  fourth  genus  is  also  represented  by  a 
single  extinct  form,  the  A.  anglicm  of  Lydekker.  In  the  United  States  we  have  some  six  (6)  species  and  five  sub- 
species of  Cormorants,  all  of  the  family  PlialncrocnracidiE.  Through  the  constant  energy  and  perseverance  of  Mr.  Lucas, 
a  large  proportion  of  these  Cormorants  are  represented  in  the  collections  of  the  U.  8.  National  Museum  by  their  skele- 
tons, and  through  his  kindness  I  have  been  enabled  to  study  and  compare  all  this  material  in  the  revision  of  the  present 
memoir.  The  collection  in  question  is  now  doubtless  the  finest  of  the  kind  in  the  world,  and  has  in  it  the  skeletons 
of  more  steganopodous  birds  than  that  of  any  other  in  existence. 


166 


MEMOIRS    OF    THE    CARNEGIE    MUSEUM 


spidllatus,  Pallas's  Cormorant,  given  by  Mr.  F.  A.  Lucas  in  the  Proceedings 
of  that  institution  for  1889  (pp.  88-94),  also  other  material  and  figures  by  the 
same  author. 

When  we  regard  the  skull  of  P.  urile  from  above,  we  observe  that  the  cranium 
is  very  flat,  and,  across  the  parietal  region,  broad.     Indeed,  though  large,  the  brain- 


st.o 


FIG.  12.     Left  lateral  view  of  the  skull  of  Phalacrocorax  urile;  nat.  size.     By  the  author,  from  a  specimen  in  the 
Smithsonian  Institution.     s(.o.,  the  occipital  style.     (See  also  Plate  XXIV.,  Fig.  15.) 

cavity  is  vertically  compressed,  and  this  is  one  of  the  first  things  to  attract  our 
attention  as  we  examine  the  skull  of  this  Cormorant.  Between  the  sharp  superior 
edges  of  the  orbits  the  frontal  region  measures  transversely  about  a  centimeter,  and 
this  too  is  the  average  width  of  the  not  very  mobile  cranio-facial  hinge.  A  broad- 
ish,  shallow,  longitudinal  groove  traverses  the  fron to-parietal  region,  and  the  well- 
marked  crotaphyte  fossre  fail  quite  to  meet  on  top  of  the  prominent,  convex  occip- 
ital elevation.  The  occipital  line  and  crest  are  very  sharp  and  ridge-like,  and  a 
free,  osseous,  occipital  style,  over  a  centimeter  and  a  half  long,  articulates  at  a  median 
point  a  short  distance  above  the  large  foramen  magnum,  where  these  lines  and 
crests  meet.  This  style  is  distally  pointed,  has  sharp  supero-median  and  lateral 
borders,  which  give  rise  to  supero-lateral  surfaces  intended  for  the  attachment,  on 
either  side,  of  the  posterior  part  of  the  temporal  muscle.  (See  Fig.  12.) 

The  upper  bony  beak  is  somewhat  broad  at  its  base  ;  is  slightly  longer  than  the 
cranium ;  narrow  for  its  anterior  half ;  edges  semi-cultrate  ;  very  moderately  decurved 
at  the  end  ;  culmen  broadly  convex  from  side  to  side ;  flat  beneath  ;  external  narial 
apertures  absent.  A  groove  passes  down  upon  either  side,  which  is  deepest  at  those 
sites  where  nostrils  occur  in  most  birds  that  have  them.  There  is  a  minute  foramen 
on  either  side,  communicating  with  the  rhinal  chamber.  The  lateral  processes  of  the 
cranium  are  -almost  entirely  aborted,  and  the  orbital  cavity  behind  freely  opens  into 
the  cranio-zygomatic  space,  and  the  cranial  wall  here  is  bulging,  smooth,  and  con- 
vex. At  the  occiput  the  usual  processes  are  fairly  well  developed,  and  the  quadrato- 
mandibular  articulation,  on  either  side,  is  located  far  posteriorly  as  in  an  alligator. 


SHUFELDT  :     OSTEOLOGY    OF   THE    STEGANOPODES 


167 


In  their  essential  characters,  the  quadrates,  the  pterygoids,  the  palatines,  and 
the  maxillo-palatines  agree  with  what  we  found  above  in  Anhinga.  Phalacrocorax 
also  has  a  small  supramaxillary,  or  as  Parker  called  it,  a  "  post-maxillary,"  and 
according  to  him  it  is  large  in  P.  carbo,  and  small  in  P.  graculus. 


FIG.  13.     Palatal  region  of  a  young  Pluilacrocurax  urile,  showing  the  maxillo-palatine  of  the  right  side. 

FIG.  14.  Dorsal  aspect  of  anterior  part  of  the  cranium  of  a  young  I'halacrocoraj;  urile,  showing  the  absence  of  a 
fronto-nasal  hinge. 

FIG.  15.  Lateral  aspect  of  beak  of  a  young  Phalacrovorax  urile,  showing  the  open  condition  of  the  nostril.  All 
three  figures  drawn  by  Mr.  F.  A.  Lucas  from  specimen  No.  12732  of  the  collections  of  the  II.  S.  Nat.  Museum,  and 
enlarged  hy  means  of  the  camera  lucida. 

Regarding  the  maxillo-palatines  and  related  bones  in  the  skull  of  a  Cormorant, 
it  seems  that  ornithotomists  do  not  quite  agree  as  to  the  exact  sutural  boundaries, 
and  it  seems  that  Mr.  W.  P.  Pycraft,  of  the  British  Museum,  some  time  ago  printed 
an  article  on  the  osteology  of  certain  steganopodes,  in  which  he  was  at  variance  with 
anatomists  upon  this  point.  Desiring  the  opinion  of  Mr.  Lucas  upon  this  point,  he 
has  kindly  furnished  me  with  the  following  remarks,  and  illustrated  them  with 
some  drawings,  which  latter  are  here  reproduced  as  Figs.  13,  14  and  15.  In  his 
communication  he  says:  "Some  difference  of  opinion  exists  as  to  just  what  portions 
of  the  maxillaries  represent  the  maxillo-palatines,  and  while  I  do  not  like  to  differ 
with  my  friend  Mr.  Pycraft  for  fear  I  be  on  the  wrong  side,  yet,  after  carefully  con- 
sidering the  subject,  the  conclusion  is  forced  upon  one  that  the  posterior  extensions 
of  the  maxillaries  are  the  maxillo-palatines." 


168  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

"By  the  kindness  of  Mr.  R.  C.  McGregor  and  Mr.  Curtis  Clay  Young  the  Museum 
some  time  ago  came  into  the  possession  of  an  extremely  good  series  of  Cormorant 
skulls  of  all  ages,  and  by  means  of  these  it  is  possible  to  trace  the  process  of  ossifica- 
tion very  well.  These  seem  to  show  that  the  desmognathism  of  the  Cormorant's 
skull  is  caused  by  the  growth  of  bone  between  the  maxillaries,  and  is  not  due  to  any 
outgrowth  of  those  bones  themselves." 

"  This  ossification  commences  between  the  backward  processes  here  considered  as 
the  maxillo-palatines  and  progresses  until  they  are  firmly  united.  The  union  of  the 
anterior  portion  of  the  maxillaries  occurs  later  and  is  due  to  the  extension  of  ossifi- 
cation into  the  tough  lining  of  the  roof  of  the  mouth,  and  there  is  frequently  a  small 
space  between  the  maxillaries  which  remains  open  for  a  long  time  if  not  perma- 
nently" (Fig.  13). 

"The  formation  of  the  fronto-nasal  hinge  (Fig.  14)  is  a  secondary  character,  the 
bones  so  overlapping  in  young  birds  that  there  is  no  freedom  of  movement  in  this 
region." 

"The  absence  of  external  narial  openings  is  also  a  secondary  character,  for  the 
young  Cormorant  possesses  perfectly  open  nostrils  while  the  cranium  is  almost  as 
schizo-rhinal  as  that  of  a  gull  (Fig.  15).  As  growth  proceeds  the  narial  openings 
become  more  and  more  restricted,  until  about  the  time  (the  exact  time  is  uncertain) 
that  the  young  birds  take  to  the  water,  not  only  the  external  openings,  but  those  of 
the  cranium  have  become  completely  filled." 

Passing  once  more  to  the  skull  in  the  adult  we  find  the  interorbital  septum  is 
unossified,  as  is  the  greater  part  of  the  anterior  wall  of  the  brain  cavity.  However, 
we  here  find  the  "foramen  rotundum"  separated  from  the  far  larger  vacuity  above, 
by  a  transverse  bony  bar.  A  subcircular  vacuity  also  occurs  in  the  mesethmoidal 
plate ;  and  the  sphenoidal  rostrum  is  not  as  large  as  the  zygoma. 

Phalacrocorax  urile  differs  from  the  Anhinga  inasmuch  as  in  it  the  pars  plana  does 
not  ossify ;  and  in  the  form  of  its  lacry  mal  bone.  One  of  these  in  this  Cormorant  is  seen 
to  be  fused  with  the  frontal  bone  and  nasal  above;  is  laterally  composed;  not  in  con- 
tact with  the  maxillary  below,  where  it  sends  outwards  a  short  process,  and  inwards 
a  longer  and  slenderer  one,  the  mesial  end  of  which  fuses  with  the  mesethmoid  (see 
Fig.  12). 

This  specimen  (No.  18982,  Coll.  U.  S.  Nat.  Mus.)  lacks  a  vomer,  and  it  was  not  to 
be  found  in  my  skeleton  of  Anhinga;  in  the  latter,  if  it  ever  existed,  it  may  have 
been  lost — but  I  see  in  another  place,  where  remarking  upon  the  osteology  of  P. 
bicristatus  (now  urile)  (Science,  N.  Y.,  v.  11,  No.  41,  Nov.  16,  1883,  p.  640),  I  have 
said  that  in  it  "we  observe  a  long  attenuated  vomer,  terminating  anteriorly  in  a  free 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  169 

pointed  extremity."  But  I  am  inclined  to  think  that  the  vomerine  ossification  is 
not  always  a  constant  character  in  these  birds.  Ossifications  of  the  eyes,  ears  and 
tongue  agree  in  the  main  with  the  corresponding  parts  in  the  Anhingidas,  and  have 
been  more  or  less  fully  described  above. 

V-shaped  in  pattern,  the  mandible  is  a  strong  bone  in  birds  of  this  family.  This 
is  due  to  the  thickness  of  the  rami,  and  not  to  their  height,  for  they  are  rather  low 
than  otherwise ;  also  to  the  unusual  firmness  of  the  dentary  ossification  with  the 
other  bones  posterior  to  it,  and  finally  to  the  total  absence  of  a  ramal  vacuity  - 
the  mandible  not  being  weakened  at  those  points  (see  Plate  XXIV.,  Fig.  17).  Each 
dentary  upon  its  mesial  aspect  shows  a  deep  longitudinal  groove.  The  articular 
ends  are  truncated  posteriorly,  though  the  postero-mesial  angles  are  somewhat  pro- 
duced. Eacli  of  these  articular  cups  appears  to  be  connected  with  |its  respective 
ramus  by  a  kind  of  neck,  which  is  directed  backwards  and  towards  the  median  line. 
When  seen  from  above,  and  the  jaw  is  articulated  in  situ,  this  gives  rise  to  rather 
an  odd-appearing  articulation.  Either  quadrate  is  thus  entirely  shut  out  of  sight, 
with  the  exception  of  its^externo-lateral  process,  the  base  of  which  does  not  come 
in  contact  with  the  mandible  at  all.  The  sides  of  the  rami  are  within  the  quadrato- 
jugal  bars,  and  rise  somewhat  above  them.  The  pterygoids,  owing  to  a  special 
notch  in  each  articular  cup,  are  thoroughly  exposed,,  but  no  more. 

Of  the  Remainder  of  the  Axial  Skeleton.  —  Seventeen  vertebrae  are  found  in  the 
cervical  region  of  P.  urile,  before  we  arrive  at  one  that  bears  a  free  pair  of  ribs.  A 
small  pair  of  rudimentary  ones  in  this  species  are  to  be  observed  in  the  eighteenth 
vertebra.  Now  in  P.  urile  these  last  are  not  liberated,  while  in  the  nineteenth  and 
twentieth  vertebrae  the  free  ribs  are  long,  well  developed,  and  have  anchylosed  upon 
them  large  unciform  processes.  In  the  leading  pair,  however,  either  upon  one  side 
or  the  other,  this  last  character  may  be  absent.  Such  is  the  case  on  the  left  side 
of  the  specimen  at  my  hand. 

P.  urile  has  its  entire  vertebral  chain  in  many  respects  quite  different  from  any- 
thing we  described  for  Anhinga.  We  do  not  meet  with  the  greatly  elongated  eight 
leading  cervicals,  and  the  abrupt  change  in  character  as  we  pass  to  the  ninth  one. 
Nothing  of  the  kind  occurs  in  the  Cormorant,  for  in  it  the  eight  leading  cervicals 
are  quite  in  harmonic  proportions  in  all  respects  with  those  that  follow  them.  We 
nevertheless  find  in  this  Cormorant  the  same  modifications,  only  in  a  far  less  marked 
degree,  in  the  eighth,  ninth  and  tenth  vertebras,  which  give  this  bird  the  power  to 
draw  back  its  head  and  with  great  rapidity  to  thrust  it  forward  again,  the  point  of 
flexure  being  between  the  vertebrae  just  mentioned.  Anhingas  catch  all  the  fish 
they  eat  by  spearing  them  with  their  sharp  beaks  while  in  active  pursuit  under 


170  MEMOIRS   OF   THE    CARNEGIE    MUSEUM 

water.  The  head  is  drawn  back  and  then  thrust  forward  like  a  spear,  with  wonder- 
ful rapidity  and  precision — the  prey  being  transfixed  on  the  closed,  lance-like 
mandibles.  When  prepared  to  deliver  the  blow,  the  angle  formed  by  the  seventh 
and  vertebrae  points  backwards,  and  the  one  between  the  eighth  and  ninth  forwards, 
the  eighth  vertebra  itself  standing  subvertically  between  them.  Gannets  and 
Herons  have  the  same  arrangement  of  these  cervical  vertebrae,  but  nothing  like  as 
well  developed  as  we  find  it  in  the  Darters.  Bitterns  show  it  well,11  as  do  all  our 
American  Herons,  and  they  transfix  their  prey,  although  they  do  not  pursue  it 
under  water  as  the  Darters  habitually  do. 

P.  urile  has  handsomely  developed  parapophysial  spines  on  its  cervical  verte- 
brae. They  are  rudimentary  on  the  atlas  and  axis,  coming  to  be  of  good  size  on  the 
third  vertebra.  From  it  on  they  gradually  increase  in  length,  but  diminish  in 
caliber,  until  we  come  to  the  tenth  cervical.  In  it  they  are  as  straight  as  sewing 
needles,  and  as  long  as  the  centrum  of  the  vertebra.  They  die  out  on  the  fifteenth 
cervical.  The  lateral  canals  are  normally  developed  and  of  good  size  in  the  third 
vertebra  at  its  anterior  part.  They  very  gradually  increase  in  size  down  the  series, 
until  we  arrive  at  the  first  vertebra  bearing  free  ribs.  On  the  other  hand  the  hypa- 
pophysial  carotid  canal  begins  in  the  fourteenth  vertebra,  and  terminates  in  the 
seventh ;  it  never  quite  closes  in  so  as  to  form  a  perfect  tube,  but  comes  very  near  it 
in  the  thirteenth  vertebra.  A  large  haemal  spine  suddenly  appears  on  the  fifteenth 
cervical,  and  the  character  persists  down  the  series,  to  include  the  leading  two  or 
three  vertebrae  of  the  pelvic  sacrum.  Haemal  spines  are  also  found  on  the  atlas  and 
axis ;  and  a  strong  neural  spine  first  appears  on  the  sixteenth  vertebra,  while  on 
the  eighteenth  to  the  twenty-third  inclusive  they  are  very  large,  strong,  oblong  in 
form,  and  much  in  contact  with  each  other  in  the  dorsal  region  of  the  spine ;  the 
various  articulations  among  the  vertebrae,  are  very  close  indeed.  Here  the  centra 
are  much  compressed  from  side  to  side ;  the  transverse  processes  narrow  and  spread- 
ing, and  these  latter  have  strong  metapophysial  spinesinterlocking  at  their  extremities. 
But  there  is  none  of  that  luxuriant  interlacing  of  ossified  tendons  that  we  see 
there,  and  on  the  neural  spines  and  anterior  iliac  margins,  as  in  Anhinga.  Phala- 
crocorax  is  more  or  less  free  from  that. 

There  are  three  pairs  of  large,  strong  dorsal  ribs,  bearing  great,  flat,  anchylosed 
unciform  appendages.  By  a  graduated  series  of  costal  ribs,  these  vertebral  ribs  join 
with  the  sternum.  The  first  pair  of  pelvic  ribs  likewise,  by  a  very  long  pair  of 
hsemapophyses,  connect  with  the  sternum.  Small  unciform  processes  also  appear 
upon  them,  but  not  on  the  last  pair  of  pelvic  ribs  that  follow  these.  Nor  do  the 

11  See  the  author's  reference  to  this  in  the  American  Bittern  in  The  Auk,  Vol.  X.,  No.  1,  January,  1893,  pp.  77-78. 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  171 

costal  ribs  of  this  pair  quite  reach  the  sternum.  On  the  left  side  in  the  specimen 
before  me  there  is  also  a  "floating  costal  rib,"  with  a  length  of  nearly  3  centimeters. 
It  lies  close  along  the  posterior  border  of  the  distal  moiety  of  the  ultimate  hsema- 
pophysis. 

This  last-mentioned  bone  in  a  specimen  of  P.  urile  articulates  with  the  sternum 
on  the  left  side,  and  no  doubt  from  time  to  time  such  will  be  found  to  be  the  case 
in  other  species  of  Phalacrocorax,  i.  e. — the  ultimate  pair  of  costal  ribs  or  haema- 
pophyses,  upon  one  side  or  the  other,  or  for  the  matter  of  that,  upon  both  sides,  may 
join  with  the  sternum  the  pelvic  ribs  to  which  they  belong. 

In  Phalacrocorax  we  find  upelvis  very  much  like  the  one  we  described  for  Anhinga. 
The  ilia  are  horizontally  spread  out  in  front,  where  they  may  be  so  thin  as  to  present 
a  number  of  perforating  foramina.  In  the'postacetabular  region  these  bones  come 
much  closer  together,  both  actually  and  relatively,  than  they  do  in  the  Darters.  The 
interdiapophysial  foramina  also  are  present,  a  row  upon  either  side  of  the  posterior 
sacral  crista,  and  they  are  very  large  just  before  we  arrive  at  the  first  caudal  vertebra. 
The  internal  iliac  borders  are  not  elevated  here  as  they  are  in  Anhinga.  Cormorants 
of  this  genus  also  have  the  large  obturator  space ;  the  enormous  ischiadic  foramen  ; 
the  rudimentary  propubis ;  and  the  same  peculiarities  of  the  postpubis. 

Posteriorly,  either  ilium  sends  back  a  conspicuous  process,  and  the  two  hold 
firmly  between  them  the  first  free  caudal  vertebra.  In  some  species,  as  P.  urile, 
they  may  grasp  two  instead  of  one.  An  ilio-ischiadic  notch  is  also  present  upon  either 
side  of  the  pelvis. 

There  seem  to  be  seventeen  vertebra?  included  in  the  pelvic  sacrum  to  the  fifteen 
we  found  in  Anhinga.  Six  of  these  are  beneath  the  fore  part  of  the  ilia  ;  two  more 
with  aborted  processes  lie  immediately  between  the  large  acetabulae  ;  two  true  dorsal 
ones  follow  these,  and  they  have  their  lateral  processes  thrown  out  as  abutments  to 
the  walls  of  the  pelvis;  finally  seven  more  so-called  uro-sacrals  are  to  be  counted 
between  these  and  the  first  caudal. 

Viewed  ventralwise,  the  pelvic  basin  is  seen  to  be  deep  and  capacious.  Another 
marked  character  on  this  aspect  is  the  strong  'ridge  or  crest  of  bone  on  either  side, 
which  extends  longitudinally  backwards  from  a  point  below  the  cotyloid  ring  to  the 
hindermost  angle  of  the  ischium.  It  is  strongest  directly  below  the  great  ischiadic 
foramen.  This  character  is  but  feebly  marked  in  the  pelves  of  the  Darters. 

There  are  six  caudal  vertebrae  and  a  pygostyle.  The  latter  is  large ;  pointed 
posteriorly,  triangular  in  form,  broad  and  flattened  at  its  lower  part  behind,  in 
front  of  which  there  is  a  haemal  spine.  Haemal  spines  are  also  found  upon  the  last 
three  caudals,  and  neural  ones  on  them  all.  These  tail  vertebrae  are  large  and  strong, 


172 


MEMOIRS    OF   THE    CARNEGIE    MUSEUM 


and  the  transverse  processes  on  the  fourth  and  fifth  extend  out  considerably  beyond 
the  others  of  the  series. 

Sternum  and  Shoulder  Girdle. — In  the  article  in  Science  cited  above  it  was  said  of 
the  sternum  of  P.  urile  that  it  had  "  two  shallow  excavations  on  either  side  of  the 
median  line,  occupying  the  entire  xiphoidal  margin  or  border"  (p.  641).  This  no 
doubt  was  a  lapsus  calami,  as  no  true  Cormorant  has  more  than  one  such  excavation 
upon  either  side  of  the  sternal  keel.  Apart  from  its  greater  size,  the  sternum  in  P. 
urile  agrees  in  almost  every  particular  with  that  bone  as  we  described  it  for  A.  an- 
hinga.  The  lateral  xiphoidal  processes,  however,  are  comparatively  not  as  long  nor 
as  narrow ;  nor  are  the  costal  processes  of  the  sternum  of  the  Cormorant  relatively  as 
lofty  or  as  slender  as  they  are  in  the  Darter.  Otherwise  the  two  bones  essentially 


FIG.  16.  Right  lateral  view  of  sternum  and  bones  of  the  shoulder-girdle  of  a  Cormorant  ( Phalaerocorax  urile),  nat. 
size,  by  the  author,  from  a  specimen  in  the  collection  of  the  U.  S.  Nat.  Museum.  (Compare  this  figure  with  Fig.  30 
of  Plate  XXVI.) 

agree.  (Compare  also  the  sternum  of  Phalaerocorax  albiventris,  PI.  XXVI.,  Fig.  30.) 
Again  upon  comparing  the  several  bones  of  the  pectoral  arch  in  these  two  forms,  we  are 
once  more  at  a  loss  to  find  any  noteworthy  differential  characters.  The  os  furcula 
in  each  are  upon  identically  the  same  pattern  ;  the  coracoids  are  alike  with  the  ex- 
ceptions that  in  the  Cormorant  the  bone  is  proportionately  not  as  long  ;  its  sternal  end 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOI'ODES  173 

is  more  expanded,  and  it  has  a  broadly  developed  "  costal  process."  In  the  case  with 
the  scapula,  we  find  that  the  blade  of  it  in  the  Cormorant  is  not  as  much  curved, 
nor  is  the  distal  end  of  the  bone  at  all  bent  outwards.  (See  Fig.  16.) 

On  the  Appendicular  Skeleton  of  P.  urile. 

Very  little  of  the  skeleton  of  this  Cormorant  is  pneumatic.  For  the  most  part 
the  bones  are  solid  and  heavy.  Apparently  air  gains  access  only  to  certain  parts  of 
the  cranium  and  lower  jaw,  other  bones  of  the  osseous  system  being  completely  non- 
pneumatic.  This  is  especially  true  of  the  skeleton  of  the  limbs,  where  all  the  bones 
typify  in  the  highest  degree  the  un aerated  variety. 

In  a  number  of  respects  the  bones  of  the  pectoral  limb  of  P.  urile  present  char- 
acters which  essentially  agree  with  those  upon  the  corresponding  bones  as  found  in 
the  arm  of  an  Anhinga,  which  characters  have  already  been  described  above.  In 
the  humerus  of  Phalacrocorax,  however,  which  is  shorter  than  the  ulna,  the  "  pneu- 
matic fossa"  is  profoundly  concave,  quite  as  much  so  as  in  those  large  species  of 
birds  in  which  the  bone  is  pneumatic,  or  even  more  so  than  in  some  which  show  that 
condition.  At  its  distal  end  the  articular  protuberance  for  the  radius  has  an  elon- 
gation at  its  proximal  extremity  which  is  bent  over  towards  the  mid-longitudinal 
axis  of  the  shaft  of  the  bone.  The  "oblique  tubercle"  for  the  ulna  is  more  hemi- 
spherical than  we  usually  find  it  in  birds.  At  the  proximal  end  of  the  ulna  we  ob- 
serve a  conspicuous  projecting  lip  of  bone,  which  contributes  an  additional  surface 
for  the  radial  articulation.  Papillae  down  the  shaft  of  this  bone  for  the  quill-butts 
of  the  secondary  feathers  are  in  a  single  row  and  rather  feebly  developed.  Both 
radius  and  ulna  are  somewhat  bowed,  and  when  articulated  in  situ  they  are  in  con- 
tact for  their  distal  moieties  while  proximally  a  good-sized  spindle-shaped  interosse- 
ous  space  occurs  between  them. 

The  characters  of  the  skeleton  of  the  hand  are  practically  the  same  as  we  found 
them  to  exist  in  the  manus  of  Anhinga.  There  are  no  distinguishing  characters  of 
any  importance. 

Gannets  have  the  skeleton  of  their  pectoral  limbs  in  many  respects  like  the 
Cormorants  and  Darters,  but  in  them  all  the  bones  are  completely  pneumatic. 
When  we  come  to  consider  the  difference  in  the  habits  of  the  representatives  of  the 
three  families,  this  is  not  so  much  to  be  wondered  at. 

Cormorants  are  more  or  less  like  the  Darters  too,  in  the  osteology  of  their  pelvic  limb. 
There  are  more  differences,  however,  to  be  found  here  than  we  discovered  upon  compar- 
ison of  the  pectoral  extremities.  Phalacrocorax  has  the  femur  proportionately  stouter, 
shorter,  and  more  bowed  in  the  antero-posterior  direction  than  it  is  in  Anhinga. 


174  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

We  also  note  that  the  pit  for  the  insertion  of  the  ligamentum  teres  is  more  elab- 
orately scooped  out,  and  the  trochanterian  protuberance  is  produced  far  more  to 
the  front  in  the  Cormorant,  such  hardly  being  the  case  at  all  in  the  Darter.  The 
fibular  and  intercondyloid  notches  are  very  deeply  sculpt,  though  anteriorly  the 
rotular  channel  is  unusually  shallow. 

The  large  trihedral  patella,  with  its  broad,  flattish  base  is,  as  Garrod  remarks, 
often  laterally  pierced  for  the  passage  of  the  tendons  of  the  ambiens  muscle.12  The 


Fia.  17.  Knee  joint  of  a  Cormorant  (Phalacrocorax  urile);  natural  size.  F,  femur;  P,  patella  (originally  de- 
scribed by  the  author  in  Science);  Fb,  fibula;  T,  tibio-tarsus.  Drawn  by  the  author  from  a  specimen  in  the  Smith- 
sonian Institution. 

FIG.  18.  Knee-joint  of  Phalacrocorax  urile,  seen  from  in  front.  Natural  size.  Letters  signify  the  same  as  in  other 
illustrations. 

cnemial  processes  of  the  tibio-tarsus  are  fairly  well  developed  and  are  confined  to 
the  anterior  aspect  of  the  head  of  the  bone,  where  we  also  see  a  strong  cnemial  crest 
rising  above  its  summit.  For  its  entire  length,  the  shaft  is  compressed  in  the 
antero--posterior  direction,  and  the  fibular  ridge  is  long — standing  well  away  from 
the  side  of  the  shaft.  Phalacrocorax  has  the  fibula  about  as  well  developed  as  we 
found  it  in  Anhinga,  it  being  complete  and  fused  with  the  tibio-tarsus  only  at  its  dis- 
tal end.  When  the  bone  is  held  vertically  the  internal  tibio-tarsal  condyle  is  the 
lower  of  the  two  on  the  extremity  of  the  shaft. 

Cormorants  have  a  tarso-metatarsus  differing  in  some  marked  particulars  from  that 
borne  in  the  Darters.  In  the  first  place  it  is  pierced  by  but  one  arterial  foramen  at 
its  trochlear  end,  and  its  mid-trochlear  process  is  the  lowest  on  the  shaft,  rather  than 
the  inner  one  as  in  the  Anhingas.  Tendinal  grooves,  and  their  dividing  lines  up 

12  Garrod,  A.  H.  Coll:  Scientif .  Mem.,  p.  198. 


SHTJFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  175 

and  down  the  shaft,  back  and  front,  also  slightly  differ,  as  does  the  form  of  the 
hypotarsus  in  a  lesser  degree. 

The  skeletal  plan  of  the  pea  in  Phalacrocorax  essentially  agrees  with  what  we 
found  in  the  Anhingidse.  We  are  to  note  the  great  length  of  the  basal  joint  of 
hallux,  and  for  its  entire  continuity,  how  muchjthe  shaft  of  the  bone  is  bowed. 

Mr.  Frederic  A.  Lucas,  Curator  of  the  Department  of  Comparative  Anatomy 
in  the  U.  S.  National  Museum,  in  describing  some  of  the  bones  of  P.  perspidllaius 
in  the  Proceedings  of  that  institution  for  1899  (Vol.  XII.,  p.  88),  remarked  that  he 
had  the  following  material  upon  which  to  base  his  studies,  and  which  had  been 
collected  by  Dr.  Leonard  Stejneger  on  Bering  Island  in  1882. 

"  Rostral    portion    of    cranium    in  "  Right  fused  metacarpals,  very  im 

advance  of  the  fronto-nasal  hinge,  with        perfect, 
attached  palatines.  "  Three  pelves,  lacking  pubic  bones. 

"  Lower  mandible.  "  Left  femur. 

"  Right  ramus  of  lower  mandible.  "  Two  left  tibiae. 

"Two  nearly  complete  sterna.  "  Right  tibia. 

"  Right  coracoid.  "  Two  left  tarsi. 

"  Right  humerus.  "  Second  cervical  vertebra. 

"Left  humerus  of  another  individual.  "  Third  cervical  vertebra. 

"  Right  ulna.  "  Ninth  (?)  cervical  vertebra. 

"  Right  fused  metacarpals. 

"  The  more  important  of  these  are  figured  on  the  accompanying  plates,  all  figures 
being  of  natural  size,  and  drawn  by  the  author. 

"  The  bones,  although  stained,  are  in  a  good  state  of  preservation,  being  but 
slightly  weathered,  and  all  are  from  thoroughly  adult  individuals. 

"For  a  better  and  briefer  description  of  these  bones  they  have  been  compared 
with  those  of  an  adult  Phalacrocorax  carbo,  and  the  opportunity  has  been  taken  to 
test,  to  some  extent,  the  value  of  the  subgenera  Urile  and  Phalacrocorax,  by  com- 
paring at  the  same  time  the  corresponding  bones  of  P.  urile  and  P.  dilophus. 

"The  former  bird  is,  for  the  species,  large  and  the  latter  somewhat  undersized, 
although  adult. 

"  The  rostrum  of  perspidllatus  is  nearly  as  long  as  in  carbo,  but  much  more 
slender,  and  is  readily  distinguished  from  it  by  the  deep,  lateral,  longitudinal 
groove  characteristic  of  the  subgenus  Urile. 

"The  under  surface  of  the  rostrum  is  less  grooved,  longitudinally,  than  that  of 
carbo  and  much  less  so  than  that  of  P.  urile  (see  PI.  XXIV.,  Figs.  13-21,  and  PI. 
VI.,  Figs.  25-28). 


176  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

"  The  palatines  are  as  long  as  those  of  carbo,  anteriorly  narrow  and  posteriorly 
wider,  conforming  in  pattern  very  nearly  to  those  of  urile,  while  dilophus  resembles 
carlo  in  this  respect. 

"  The  trans-palatine  angle  is  more  rounded  than  in  carbo,  much  more  than  in 
urile,  resembling  in  this  dilophus. 

"  The  inner  portion  of  the  post-palatine  is  less  produced  ventrally  than  in  carbo, 
and  the  pterygoid  articulation  wider  and  flatter  than  in  carbo,  the  palatine  thus 
lacking  the  keel  present  in  carbo. 

"The  same  differences  are  found  between  the  same  parts  of  urile  and  dilophus. 

"  The  maxillo-jugal  bar  is  as  long  as  that  of  carbo  but  more  slender. 

"The  lower  mandible  is  slightly  shorter  and  decidedly  weaker  than  that  of 
carbo,  and  the  lower  mandible  of  urile  is  proportionately  still  weaker  than  that 
of  dilophus. 

"The  dentary  portion  of  the  mandible  is  more  deeply  grooved  along  the  inner 
surface  than  that  of  carbo,  being  comparatively  the  same  as  in  urile. 

"The  cutting  edges  of  the  mandible  are  comparatively  straight  as  in  carbo  and 
dilophus,  but  urile  differs  from  all  three  in  having  the  mandible  distinctly  recurved. 

"The  sternum  is  transversely  flatter  than  that  of  carbo,  being  a  trifle  more  flat- 
tened even  than  that  of  urile.  The  carina  is  also  shorter  than  in  urile,  but  in  size 
and  general  appearance  the  sterna  of  perspicillatus  and  urile  resemble  one  another 
very  closely. 

"From  manubrium  to  meso-xiphoid  that  sternum  is  13  mm.  shorter  than  that 
of  carbo,  being  exactly  as  long  as  that  of  urile. 

"  The  proportion  of  carina  to  total  length  is  shorter  than  in  either  carbo  or  urile, 
the  sternum  from  anterior  end  of  carina  to  mesoxiphoid  measuring  2  cm.  less  than 
that  of  carbo  and  4  mm.  less  than  that  of  urile. 

"  Between  the  costal  borders  the  sternum  is  slightly  wider  than  in  either  ca.rbo  or 
urile. 

"The  rudimentary  manubrium,  like  that  of  urile,  lies  in  the  plane  of  the  body  of 
the  sternum,  while  in  carbo  and  dilophus  the  manubrium  lies  in  the  plane  of  the 
keel. 

"If  a  line  be  drawn  between  the  costal  processes  it  will  be  found  that  the  coracoid 
articulations  project  less  beyond  this  line  and  form  a  more  obtuse  angle  with  one 
another  than  they  do  in  carbo,  and  the  same  is  true  of  urile  as  compared  with 
dilophus.  The  sternum  is  non-pneumatic,  as  in  urile,  but  in  carbo  and  dilophus 
good-sized  foramina  pierce  its  dorsal  face  just  back  of  the  ridge  formed  by  the  cora- 
coidal  groove. 


SHUFELDT  :     OSTEOLOGY    OF   THE    STEGANOPODES 


177 


"  It  is  certainly  interesting  to  find  the  sterna  of  these  two  representatives  of  the 
snbgenera  Phalacrocorax  and  Urile,  respectively,  agreeing  with  one  another  in  these 
slight  structural  points. 

"  Articulations  are  present  for  five  pairs  of  ribs,  the  same  number  as  in  carbo.  One 
specimen  of  urile  has  four  pairs  of  articulations,  another  has  five  on  the  left  side  and 
four  on  the  right,  and  dilophus  has  but  four  pairs  of  costal  facets. 


\ 


Bones  of  Pallas'  Cormorant.     Natural  size.     After  Lucas. 

Flo.  19.     Ventral  aspect  of  rostrum.      FIG.  20.     Lateral  aspect  of  rostrum.       Fici.  21.     Right  ramus  of  lower 
mandible,  external  aspect.     FIG.  22.     Right  ramus  of  lower  mandible,  internal  aspect.     FIG.  23.     Right  metacarpals. 


178 


MEMOIRS    OF    THE    CARNEGIE    MUSEUM 


"The  number  of  ribs  articulating  with  the  sternum  is,  however,  subject  to  slight 
variations,  especially  among  water  birds,  and  without  an  extensive  series  of  speci- 
mens it  is  a  little  difficult  to  be  sure  of  the  normal  number. 


Bones  of  Pallas'  Cormorant.     Natural  size.     After  Lucas. 

Flo.  24.     Right  coracoid,  ventral  aspect.     FIG.  25.     Sternum,  ventral  aspect.     Flo.  26.     Femur,  anterior  aspect. 
FIG.  27.     Tarsus,  anterior  aspect.     FIG.  28.     Tibia,  anterior  aspect. 


SHUFELDT  :     OSTEOLOGY'    OF   THE    STEOANOPODES  1  79 

"  The  coracoid  is  of  the  same  length  as  that  of  carbo,  10  mm.  longer  than  in  urile; 
but,  while  the  proximal  end  is  but  little  heavier  than  in  carbo,  the  shaft  and  espe- 
cially the  distal  end  are  much  more  massive. 

"  The  epicoracoid  is  prolonged  upward  into  a  sharper  hook  than  in  any  of  the 
other  species  at  hand,  but  this  process  is  subject  to  considerable  "variation  with  age 
or  in  various  individuals. 

"  One  humerus  is  a  little  longer  than  that  of  carbo,  the  other  is  of  exactly  the  same 
length ;  both  are  much  stouter,  especially  in  the  proximate  half. 

"The  humerus  is  practically  non-pneumatic,  the  foramina  being  very  minute, 
while  the  pneumatic  foramina  of  carbo,  though  not  large,  are  readily  seen. 

"The  humerus  of  urile  differs  from  that  of  dilophus  precisely  as  that  of  per- 
spicillatus from  carbo. 

"The  ulna  is  distinguishable  from  that  of  carbo  only  by  its  greater  weight,  and 
the  same  may  be  said  of  the  humerus  of  urile,  as  compared  with  that  of  dilophus. 

"  The  fused  metacarpals  are  slightly  shorter  and  slightly  stouter  than  in  carbo, 
and  here  again  the  same  differences  are  observable  between  the  metacarpals  of  urile 
and  dilophus. 

"The  'sacrum,'  as  a  whole,  is  as  long  as  that  of  carbo,  but  its  component  parts 
are  more  heavily  built. 

"  It  comprises  six  pre-sacrals,  two  true  sacrals,  and  nine  post-sacrals,  and  the 
three  '  sacra  '  of  perspicillatus  agree  with  one  another  in  these  particulars. 

"  Phalacrocorax  carbo  has  six  pre-sacrals,  two  true  sacrals,  and  nine  or  ten  post- 
sacrals.  P.  urile  has  six,  two,  eight,  and  dilophus  six,  two,  nine. 

"  The  hypapophyses  of  the  anterior  three  vertebra  have  been  broken  off,  but 
although  the  compressed  centra  are  larger  than  in  carbo,  the  hypapophyses  seem  to 
have  been  smaller. 

"  The  six  pre-sacrals  present  few  salient  characters,  but  the  diapophyses  of  the 
fourth  vertebra  lie  at  right  angles  to  the  vertebral  column,  while  in  the  three  other 
species  the  diapophyses  of  this  vertebra  are  directed  forward. 

"  The  sacral  and  immediate  post-sacral  vertebrae  vary  in  the  development  of 
their  parapophyses  in  all  four  species  under  consideration. 

"  In  all  three  specimens  of  perspicillatus  the  two  true  sacrals  bear  no  parapophyses, 
while  the  two  succeeding  vertebrae  have  them  extended  to,  and  anchylosed  with, 
the  ilium. 

"The  diapophyses  and  parapophyses  of  these  vertebra  are  united  by  a  thin 
plate  of  bone,  but  that  this  is  due  to  age  is  shown  by  the  condition  obtaining  in  the 
other  species. 


180  MEMOIRS    OF    THE    CARNEGIE    MUSEUM 

"  These  latter  also  indicate  that  the  canal  formed  by  these  processes,  the  centra 
of  their  vertebrae  and  the  ilium,  is  larger  on  the  right  side  than  on  the  left,  and  that 
it  is  the  first  obliterated  on  the  left  side. 

"  In  carbo  neither  the  sacrals  nor  the  second  post-sacral  bear  parapophyses, 
although  these  are  present  on  the  first  post-sacral,  uniting  it  firmly  with  the  ilium. 

"  In  one  example  of  urile,  slender,  but  well-marked  parapophyses  connect  the 
two  sacrals  with  the  ilia. 

"  In  another  and  much  smaller  specimen  the  second  sacral  has  a  parapophysis 
on  the  left  side,  there  being  no  parapophyses  on  the  first  sacral. 

"  In  both  specimens  of  urile  the  first,  but  not  the  second,  post-sacral  bears  para- 
pophyses. Finally,  dilophus  has  strong  parapophyses  on  the  second  sacral  and  first 
post-sacral,  but  none  on  the  second  post-sacral. 

"The  variation  in  the  sacral  region  of  these  specimens  is  not  only  interesting  in 
itself,  but  interesting  from  the  fact  that  it  is  unusual  for  parapophyses  to  be  present 
at  all  on  the  true  sacral  vertebrse  of  birds. 

"Viewed  from  above  the  ridge  formed  by  the  confluent  spinous  processes  of  the 
'sacrals'  is  wider  than  in  carbo,  and  the  interpophysial  foramina  are  nearly  closed, 
while  in  carbo  they  are  very  open. 

"  Although  these  characters  depend  to  some  extent  on  age,  they  do  not  entirely, 
and  the  same  differences  exists  between  the  '  sacra '  of  urile  and  dilophus  as  between 
those  of  perspicillatus  and  carbo. 

"The  pelvis  is  much  more  rugose  than  in  carbo,  all  attachments  for  muscles  be- 
ing strongly  emphasized. 

"The  anti-trochanter  is  placed  further  back  than  in  carbo,  and  is  much  more 
rounded,  thus  affording  more  play  to  the  femur. 

"  Just  back  of  the  anti-trochanter  the  outer  edge  of  the  ilium  is  raised  and  thick- 
ened, forming  a  flat,  subtriangular  spot,  but  proportionately  smaller  than  in  per- 
spicillatus. 

"  Back  of  this  flattened  portion  the  dorsal  edge  of  the  ilium  is  bent  outward, 
making  this  part  of  the  ilium  outwardly  concave,  where  in  carbo  it  is  convex. 

"The  post-ilia  of  carbo  and  dilophus  round  gently  outward  and  downward 
throughout  their  entire  length  from  their  junction  with  the  diapophyses. 

"Viewed  from  the  side  the  dorsal  outline  of  the  'sacrum'  is  slightly  decurved, 
while  that  of  carbo  is  very  nearly  straight  and  the  same  difference  exists  between 
urile  and  dilophus. 

"The  acetabulum  is  slightly  larger  and  forms  more  nearly  a  perfect  circle  than 
in  carbo. 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES 


181 


"The  ilio-ischiatic  foramen  is  subelliptical  and  wide,  the  longitudinal  diameter 
being  nearly  twice  the  vertical,  while  in  carlo  this  foramen  is  more  pointed  pos- 
teriorly and  narrower,  the  length  being  more  than  three  times  the  height. 

"  In  consequence  of  the  size  of  this  foramen  the  distance  from  the  dorsal  edge  of 
the  ilium  to  the  ventral  edge  of  the  ischium  is  much  greater  than  in  carlo. 

"The  bar  of  the  ischium  bounding  the  obturator  space  is  sharp-edged,  rugose, 
and  concave  exteriorly  on  the  posterior  portion,  while  the  corresponding  portion  of 
the  ischium  in  carlo  is  comparatively  smooth  and  slightly  convex  posteriorly. 


Bones  of  Pallas'  Cormorant.     Natural  size.     After  Lucas.     FIG.  29.  Left  lateral  aspect  of  pelvis.     Flo.  30.  Dorsal 
aspect  of  pelvis.     The  long,  sweeping  post-pubic  bone  was  broken  off  and  lost  from  this  bone  when  it  was  discovered. 


182  MEMOIRS    OF   THE    CARNEGIE    MUSEUM 

"  The  posterior  border  of  the  ischium  is  straighter  than  in  carbo  and  the  ilio-pubic 
articulation  one  third  shorter. 

"The  femur  is  5  mm.  longer  than  that  of  carbo,  in  every  way  much  more  massive, 
and  with  all  the  muscular  ridges  more  pronounced,  while  curiously  enough  it  is 
more  pneumatic,  having  several  foramina  in  the  ventral  aspect  of  the  neck  that  are 
lacking  in  carbo. 

"There  is  nothing  to  distinguish  the  femur  of  wile  from  one  of  dilophus  of  the 
same  length,  and  of  the  two  that  of  dilophus  is  slightly  the  heavier. 

"  But  in  the  specimen  of  urile  in  which  the  humerus  corresponds  in  length  to  that 
of  dilophus,  the  femur  and  tibia  are  both  longer  and  heavier  than  in  dilophus,  and 
the  tar_sus  a  little  lighter. 

"  The  phalanges,  again,  are  more  massive  in  urile  than  in  dilophus. 

"  The  smallest  of  the  three  tibiae  is  slightly  longer  than  that  of  carbo,  the  cnemial 
crest  is  more  expanded,  and  the  cnemial  ridges  farther  apart  and  more  pronounced. 

"  The  distal  extremity  of  the  tibia  is  also  wider  than  in  carbo,  but  at  its  smallest 
diameter  the  shaft  is  no  larger. 

"The  muscular  ridges  and  grooves  are  more  marked  than  in  carbo,  but  in  the  ab- 
sence of  more  material  and  making  due  allowance  for  individual  variation,  it  is  dif- 
ficult to  point  out  characters  which  definitely  distinguish  the  tibiae  of  the  two  birds. 

"The  tarsus  is  of  the  same  length  as  in  carbo,  but  much  wider,  and,  as  through- 
out, with  all  the  ridges  more  pronounced. 

"  Little  can  be  said  concerning  the  three  cervical  vertebrae,  except  that,  unlike  the 
other  bones,  they  are  less  strongly  built  than  the  corresponding  bones  in  carbo. 

"  From  the  foregoing  notes  it  will  be  seen  that  the  differences  existing  between 
corresponding  bones  of  perspicillatus  and  carbo  also  exist  between  the  same  bones  of 
urile  and  dilophus,  and  that  conversely  perspicillatus.  and  urile  agree  with  one  another 
as  do  carbo  and  dilophus. 

"  The  subgenera  Phalacrocorax  and  Urile,  therefore,  seem  to  rest  on  good  struc- 
tural foundations,  each  being  characterized  by  internal  as  well  as  external  characters. 

"  Unfortunately  no  skull  of  perspicillatus  is  to  be  had,  but  the  crania  of  carbo  and 
dilophus  agree  with  one  another,  while  differing  strikingly  from  the  cranium  of 
urile. 

"  From  the  harmony  of  the  other  parts  its  not  assuming  too  much  to  suppose 
that  the  skull  of  perspicillatus  would  resemble  that  of  urile." 

"  With  the  exception  of  the  sternum  the  greater  size  of  the  bones  distinguishes 
those  of  perspicillatus  from  those  of  urile,  while  well-marked  differences  of  shape  or 
proportion  exist  between  the  corresponding  bones  of  perspicillatus  and  carbo. 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES 


183 


MEASUREMENTS    (IN   MILLIMETERS)  OF  CORRESPONDING   BONES  OF   PHALACROCORAX 
PERSPICILLATUS,  CARBO,  URILE,  AND  DILOPHUS.     [FROM  LlJCAS.] 

(All  measurements  are  in  a  direct  line  and  not  along  curves.) 


P.  perspi- 

cillalus 
( National 

.Museum, 
17041). 


P.  earbo  P.  urile  i    P.  dilophus 

(Yale  College  (National  (National 

Mnsenm,  Museum,  Museum, 

535).  12502).  18050). 


Rostrum  : 

Tip  of  mandible  to  extremity  of  maxillo-jugal  bar 134  140 

Maxillo-jugal  bar j  68  69 

Tip  of  mandible  to  posterior  end  of  palatine 109  117 

Width  across  nasals,  at  fronto-nasal  hinge j  21      .  20 

Lower  mandible  : 

Length  of  ramus 139  144 

Greatest  height  of  ramus  j  13  13 

Sternum  : 

Anterior  end  of  carina  to  mesoxiphoid 104  119 

Manubrium  to  mesoxiphoid 83  97 

Depth  of  carina 28  33 

Width  across  articulations  of  first  rib 64  66 

Width  across  articulations  of  fourth  rib 63  59 

Coracoid  : 

Length 84  87 

Breadth  of  sternal  articulation 25  25 

Greatest  distal  breadth 18  17 

Humerus  : 

Length 170  170 

Greatest  proximal  breadth 30  28 

Greatest  diameter  of  shaft  midway  between  extremi- 
ties    11  9 

Greatest  distal  breadth...  21  20 
Ulna  : 

Length 190  178 

Greatest  proximal  breadth j  21  18 

Greatest  diameter  of  shaft  midway  between  extremi-1 

ties 8  7 

Pelvis  : 

Greatest  length  of  ilium I  151  152 

From  anterior  border  of  ilium  to  external  angle  of  I 

anti-trochanter I  72  65 

Greatest  width  of  ilia  in  advance  of  acetabula |  48  44 

Least  width  of  ilia  in  advance  of  acetabula 23  23  + 

Width  between  outer  extremities  of  anti-trochanters.  43  46 

Length  of  ilio-ischiatic  space '  42  41 

Greatest  width  of  ilio-ischiatic  space 18  13 

From  dorsal  edge  of  ilium,  above  the  ilio-ischiatic 

foramen,  to  ventral  edge  of  iscbium 28  23 

Length  of  ilio-pubic  articulation 21  28 

Between  posterior  terminations  of  ischia I  46  40 

Femur  : 

Length 74  70 

Greatest  proximal  width 21  19 

Greatest  diameter  midway  between  extremities 11  10 

Greatest  distal  width 22  18 

Tibia  : 

Length 140  127 

Width  across  cnemial  ridges 15  13 

Width  at  distal  end  of  articulation  with  fibula 15  13 

Least  transverse  diameter  of  shaft 8  8 

Distal  width 16  15 

"Tarsus"  : 

Length 71  72 

Proximal  transverse  width .- 19  16 

Distal  width 20  18 


108 
56 
91 
13 

112 


97 
84 
31 
64 
60 

71 
24 
16 

140 

25 

10 
18 


122 

58 
42 
19 
37 
32 
13 

23 
15  + 
42 

66 

16 

9 

16 

117 
11 
11 

7 
12 

60 
14 
15 


105 
56 
86 
14 

110 
12 

91 
76 
26 
54 
51 

70 
20 
13 

140 

23 

8 
17 


120 

49 
38 
18 
33 
38 
10 

19 
23 
40 

55 
15 
8 
15  + 

102 

11 

13 

7 

13 

62 
14 
14 


184 


MEMOIRS    OF    THE    CARNEGIE    MUSEUM 


"  P.  perspieillatus  appears  to  have  been  a  much  heavier  bird  than  carbo,  and  a  bird 
of  weaker  flight ;  with  more  robust  and  muscular  legs,  and  a  more  slender  and  more 
feeble  head  and  neck. 


Skull  and  Jaw-bones  of  Pallas'  Cormorant.     (After  Lucas.) 

Flo.  31.  Phalocrocorax  perspicillatua,  inferior  aspect  of  cranium.  The  anterior  and  posterior  portions  are  from  dif- 
ferent individuals.  (Nat.  size. ) 

Flo.  32.   Phalacrocorax  perspieillatus,  left  ramus  of  jaw,  external  aspect.      ( Nat.  size. ) 

FIG.  33.  Phalacrocorax  perspieillatus,  mandible  and  left  palatine,  external  aspect.     (Nat.  size.) 

"  In  comparing  the  tables  of  measurements  it  must  be  said  that  they  do  not 
adequately  convey  the  impression  produced  by  a  comparison  of  the  bones  them- 
selves. Thus,  in  the  measurements  of  the  lower  mandible  the  greatest  vertical  width 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  .  185 

is  comparatively  as  in  carbo,  but  from  this  point  the  ramus  tapers  rapidly  either  way 
so  that,  as  a  whole,  the  mandible  is  much  weaker  than  that  of  carbo. 

"So  too  with  the  humerus,  where  the  greatest  proximal  width  is  only  2  mm. 
greater  than  in  carbo,  although  the  bone  in  its  entirety  is  much  more  stoutly  built." 

In  a  following  volume  of  the  Proceedings  of  the  U.  S.  National  Museum,  in 
which  Mr.  Lucas  described  the  above  specimens  of  bones  of  P.  perspicillatus,  he 
on  subsequent  pages  also  described  the  skull  of  this  species,  and  presented  other 
data  of  importance  having  reference  to  the  Phalacrocoraddss  (Vol.  XVIII. ,  pp.  717- 
719,  Pis.  XXXIV.-XXXV.). 

This  second  lot  of  bones  were  likewise  obtained  by  Dr.  Stejneger  at  Bering 
Island  in  1895,  or  thirteen  years  after  the  first  specimens  were  collected  by  him. 
A  cranium  and  a  sternum  of  P.  perspicillatus  are  found  in  this  second  installment, 
and  they  are  very  important  discoveries. 

The  cranium  is  now  in  the  collection  of  the  Museum  (No.  19417,  U.  S.  N.  M.). 
"In  its  general  contour,"  says  Mr.  Lucas  in  his  paper  referred  to  above,  "it  most 
closely  resembles  that  of  P.  penicillatus  among  existing  cormorants,  but  is  decidedly 
larger,  and  is  proportionately  wider  than  in  that  species,  while  the  beak  is  shorter. 
As  far  as  mere  size  is  concerned,  the  skull  of  an  adult  male  of  P.  carbo  would  be  as 
long  as  that  of  P.  perspicillatus,  but  the  latter  is  much  wider  and  is  more  depressed. 
The  cranium  is  readily  distinguished  from  that  of  P.  urile  by  its  greater  size  and  less 
depression,  and  by  having  a  proportionately  stouter  beak,  whose  ridge  lacks  the 
slight  but  characteristic  emargination  found  near  the  base  of  the  beak  in  P.  urile. 

"As  a  matter  of  fact,  the  differentiation  of  cormorants  into  species  with  grooved 
beaks  and  those  without  does  not  exist,  so  far  as  the  bony  beak  is  concerned.  Some 
have  deeper  grooves  than  others,  but  all  have  more  or  less  of  a  furrow  along  the  side 
of  the  mandible,  and  there  is  every  degree  of  gradation,  from  such  well-furrowed 
beaks  as  those  of  P.  albiventris  and  P.  magellanicus  to  the  shallow  grooves  of  P.  melan- 
oleucus  and  P.  carbo. 

"  Pallas's  Cormorant  shows  a  marked  difference  from  all  others  examined  in  the 
development  of  the  lateral  ethmoid.  In  other  species  the  lachrymal  sends  a  process 
inward  which  fuses  with  a  spur  from  the  mesethmoid  to  form  a  more  or  less  L-shaped 
bar  of  bone,  uniting  the  frontal  and  mesethmoid.  A  small  spur,  arising  from  the 
inferior  inner  angle  thus  formed,  represents  the  lateral  ethmoid,  and  this  is' usually 
but  little  developed,  being  largest  in  P.  penicillatus  and  obsolete  in  P.  urile.  In  P. 
perspicillatus  there  is  a  lateral  ethmoid  plate,  complete  save  for  an  opening  above, 
being  the  retention  by  ossification  of  a  cartilaginous  plate  found  in  the  nestling  of 
P.  urile  before  the  nostrils  have  become  closed.  The  maxillopalatines  are  also 


186 


MEMOIRS   OF   THE    CARNEGIE    MUSEUM 


slightly  better  developed  than  in  any  existing  cormorant,  and  while  the  difference 
is  small,  still  it  does  exist,  and  here  again  it  is  seen  by  comparison  to  be  the  develop- 
ment of  a  character  found  in  young  birds. 


34 


36 


Crauia  of  various  Cormorants.     ( After  Lucas. ; 

FIG.  34.     Phalacocorax  penidllatus. 

Fid.  35.     Phalacrocorax  perspicillatus. 

Flo.  36.      Phalacrocorax  carlo.     (Two  thirds  natural  size  ;  from  photographs. ) 

"  Difference  exist  between  P.  perspidllatus  and  other  cormorants  by  the  presence 
of  a  narrow  bar  of  bone  forming  two  precranial  cavities  where  but  a  single  opening 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES 


187 


exists  in  allied  species,  and  in  the  comparatively  small  size  and  regular  lyrate  form 
of  these  openings.  From  these  conditions  it  will  be  seen  that  there  is  in  the  cranium 
an  excess  of  ossification  over  that  found  in  other  cormorants.  While  no  bar  of  bone 
has  been  found  in  other  species,  there  are  hints  of  it  in  some,  thus,  P.  penicillatus 
and  P.  magellanicus,  in  the  shape  of  a  little  bony  spike  running  upward  from  the 
alisphenoids,  and  it  is  not  impossible  that  the  complete  bar  may  be  found  in  some 
very  old  individual.  This  is  the  more  probable  because  in  the  young,  of  P.  urile  at 
least,  there  is  a  bar  of  cartilage  occupying  the  place  of  the  bar  of  bone  found  in 
Pallas'  Cormorant. 

MEASUREMENTS13   OF    SPECIES   OF    PHALACROCORAX.14       [FROM  LUCAS.] 

STERNUM. 


P.  perspicillatus, 
male 
(U.  S.  N.  M., 
No.   19417). 

P.  carbo, 
male  (Yale 
College, 
No.  535). 

P.  penicillatus 
(U.  S.  N.  M., 
No.   18535). 

P.  urile, 
male 
(U.  S.  N.  M., 
No.  12502). 

Anterior  end  of  carina  to  mesoxiphoid  

mm. 
13215 

mm. 
119 

mm. 
101 

mm. 
104 

Manubrium  to  mesoxiphoid.  . 

109 

97 

87 

90 

Depth  of  carina  

4Q15 

33 

22 

25 

Width  across  articulations  of  first  rib 

84 

66 

60 

70 

Width  across  articulations  of  fourth  rib... 

72 

59 

58 

65 

SKULL. 


1  P.  perspicillaius, 
male 
(U.  S.  N.  M., 
No.  19417). 

P.  earbo, 
male 

(U.  S.  N.  M., 
No.   18851). 

P.  peniciUiitus 
(U.  S.  N.  M., 
No.  940). 

P.  urile, 
male 

(U.  S.  N.  M., 
No.   12502). 

mm, 
Tip  of  mandible  to  occipital  condyle  14816 

mm. 
135 

mm. 
141 

mm, 
116 

Fronto-nasal  hinge  to  articulation  for  occip- 
ital style  69 

61 

62 

55 

Across  anterior  part  of  frontals  22 

20 

19 

13 

Across  postorbital  processes                                             39 

31 

32 

25 

Across  squamosal  processes.               .                              45 

36 

37 

32 

Across  exoccipital  processes...                                       40 

33 

33 

26 

"  The  sternum  (No.  1941 7,  U.  S.  N.  M.)  found  with  the  present  series  of  bones  is 
important,  as  its  size  indicates  it  to  be  that  of  a  male,  and  shows  the  sternum  previ- 
ously described  to  have  been  that  of  a  female,  or  possibly  even  that  of  a  male  of  P. 
urile.  It  is  very  much  larger  than  any  sternum  of  P.  urile,  and  much  larger  even 
than  the  large  specimen  of  P.  carbo,  used  for  comparison.17  The  present  sternum  is 

13The  measurements  are  in  a  straight  line. 

"Proc.  U.  S.  Nat.  Mus.,  XII.,  1889,  p.  88. 

15 Estimated,  owing  to  breakage. 

1S Taken  from  rostrum  of  one  bird  and  calvarium  of  another. 

17  Proc.  U.  S.  Nat.  Mus.,  XII.,  1889,  pp.  88-94. 


188  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

thus  in  harmony  with  the  other  bones,  and  aids  'materially  in  emphasizing  the 
superior  size  of  P.  perspicillatus. 

"  The  appended  tables  give  the  measurements  of  the  cranium  and  sternum  here 
described,  compared  with  the  corresponding  parts  of  other]  species.  The  measure- 
ments of  the  previously  described  sternum,  ascribed  to  P.  perspicillatus,  are  repeated 
and  an  error  of  the  first-given  table  corrected.  The  length  from  anterior  end  of 
carina  to  end  of  meso xiphoid  is  said  to  be  104  mm.,  when  it  should  have  been 
90  mm. 

Unfortunately  the  skull  of  P.  carbo  now  available  is  smaller  than  that  of  the 
individual  used  as  a  term  of  comparison  in  the  previous  paper18  on  Pallas' 
Cormorant." 

Additional  information  in  regard  to  the  osteology  of  the  Phalacrocoracidss  will 
be  found  further  on  in  the  present  memoir,  as  well  as  under  the  explanation  of  the 
plates  ai  its  close. 

Osteology  of  the  Pelecanidse. 

(Plate  XX VII.,  Figs.  31-41  ;  Plate  XXVIII.,  Fig.  42,  and  Plate  XXX.,  Fig.  49.) 

Sometime  during  the  year  1864,  the  writer  collected  on  Indian  Cay  of  the 
Bahama  Banks,  a  fine  adult  male  specimen  of  Pelecanus  fuscus.  From  it  I  took  the 
skull,  and  have  it  before  me  at  the  present  writing. 

Measuring  from  the  transverse  cranio-facial  groove  we  find  the  osseous  superior 
mandible  in  this  specimen  to  be  somewhat  less  than  four  times  as  long  as  the  remain- 
ing part  of  the  skull.  A  vertical  section  made  through  the  middle  of  the  posterior 
third  of  this  mandible  at  right  angles  to  its  long  axis  gives  an  elliptical  figure,  with 
the  minor  axis  in  the  horizontal  plane.  The  anterior  two  thirds  has  a  sharp  lateral 
edge,  while  the  extremity  is  armed  with  a  powerful  decurved  hook.  About  half  of 
the  fore  part  of  this  enormous  beak  is  compressed  from  above  downward,  a  com- 
pression that  is  accompanied  by  a  gradual  widening  of  the  bone  to  near  the  end, 
where  it  slopes  in  toward  the  hook  in  the  median  line. 

The  maxillo-palatines  constitute  a  great  spongy  mass  that  fills  up  a  space  anterior 
to  the  rhinal  chamber.  They  unite  in  the  median  line,  are  bounded  above  by  the 
premaxillary,  below  by  the  united  palatines,  while  the  anterior  extremity  of  the 
maxillary  fuses  with  the  mass  at  about  its  middle  on  either  side.  (Compare  with 
Figure  36,  Plate  XXVII.) 

In  form  this  maxillo-palatine  mass  is  wedge-shaped,  with  the  broad  end  anchy- 
losed  with  the  under  side  of  the  united  nasal  processes  of  the  premaxillary. 

18  Loc.  cit. 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  189 

Posteriorly  its  wall  is  composed  of  compact  tissue,  being  at  right  angles  to  the 
longitudinal  axis  of  the  skull.  It  slants  from  the  under  side  of  the  cranio-facial 
hinge  to  the  anterior  margin  of  a  median  foramen,  seen  just  anterior  to'  the  keel 
which  is  formed  by  the  union  of  the  palatines  behind. 

This  posterior  maxillo-palatine  wall  has  a  cleft  in  its  lower  two  thirds,  while  two 
conical  pits,  placed  side  by  side,  lined  with  compact  osseous  tissue,  occupy  its  upper 
third.  They  have  their  bases  opening  in  the  rhinal  chamber,  and  their  apices  are 
pierced  by  the  small  subcircular  nostrils,  one  in  each  conical  passage. 

The  hinder  half  of  the  jugal  bar  is  compressed  from  side  to  side,  slightly  dilated, 
with  its  end  crooked  up,  and  in  life  simply  bound  to  the  upper  and  outer  side  of 
the  quadrate. 

The  body  of  a  lacrymal  fuses  completely  with  the  cranial  elements  above,  its 
upper  surface  assisting  in  forming  the  smooth  superfices  of  the  frontal  region.  This 
is  also  the  case  in  P.  sharpei  (PI.  XXVII.,  Fig.  37).  From  this  portion  it  sends  down- 
ward and  slightly  backward  a  descending  process.  This  is  composed  of  a  cylindri- 
cal pedicel  for  its  upper  third  and  an  antero-posteriorly  compressed  portion  for  the 
lower  two  thirds.  It  fails  to  reach  the  maxillary,  its  tip  remaining  free  just  above 
that  perpendicularly  compressed  bar  which  passes  immediately  beneath  it. 

The  interorbital  septum  is  entire,  with  the  exception  of  a  semicircular  perfora- 
tion, which  is  immediately  in  front  of  the  aperture  in  the  anterior  wall  of  the  brain- 
case  that  gives  egress  to  the  optic  nerves. 

Each  olfactory  has  a  small  foramen  in  either  orbit  at  its  usual  site;  the  track  for 
the  nerve  being  a  broad,  shallow  groove  beneath  the  orbital  vault. 

The  mesethmoid  is  very  deep ;  its  anterior  border  is  sharp  and  thin.  Commencing 
in  the  aperture  of  the  angle  between  the  pterygoidal  shafts,  it  is  carried  directly 
upward  and  forward  to  the  expanded  portion  beneath  the  roof  of  the  cranio-facial 
region,  the  edge  meeting  the  median  division  of  the  maxillo-palatines.  (For  figures 
illustrating  the  skull  of  the  Brown  Pelican  see  my  memoir  on  the  "Osteology  of  the 
Tubinares  and  Steganopodes,"  Proceedings  U.  S.  Nat.  Museum,  1888,  Vol.  II., 
pp.  311-315.) 

The  lower  fourth  of  this  ethmoidal  border  is  thickened  and  rounded  for  the 
articulation  of  the  palatine  and  pterygoidal  heads. 

Coming,  as  usual,  from  the  anterior  apex  of  the  basi-temporal  triangle,  the  other 
portion  of  the  rostrum  is  decurved  and  meets  the  point  referred  to  above  in  the 
angle  between  the  pterygoids, 

A  quadrate  is  a  very  large  bone  with  a  broad,  triangular  process.  Its  mastoidal 
head  can  hardly  be  said  to  be  divided  into  two,  as  in  most  birds,  for  the  division  is 


190  MEMOIRS    OF    THE    CARNEGIE    MUSEUM 

so  very  slight  and  faintly  marked;  and  a  large  pneumatic  foramen  is  seen  upon  its 
outer  side — a  very  unusual  place  for  this  aperture. 

Its  mandibular  foot  is  narrow  antero-posteriorly  and  very  wide  transversely. 
Two  facets  occupy  its  lower  surface,  separated  from  each  other  by  a  concave  notch 
which  is  deepest  anteriorly. 

The  bone  also  presents  a  smooth  articular  surface  for  the  quadrato-jugal  at  the 
point  above  mentioned,  while  a  large  convex  facet  is  offered  to  the  pterygoidal  cup 
of  the  pterygoid  of  the  corresponding  side. 

We  find  the  external  openings  to  the  ear  to  be  very  small,  and  hid  from  sight 
upon  direct  lateral  view  by  the  quadrate.  A  sphenotic  process  is  well  developed, 
but  the  mastoidal  one  is  simply  a  roughened  line ;  between  the  two  is  a  wide  crota- 
phyte  valley  leading  from  the  fossa  of  the  same  name,  which  is  here  small,  incon- 
spicuous, and  entirely  lateral. 

The  orbital  cavity  itself  is  thus  seen  to  be  deep  and  capacious,  lacking  bony  walls 
principally  upon  its  inferior  and  anterior  aspects.  They  are  more  complete  in  P. 
sharpei  (PI.  XXVII.,  Fig.  37). 

Upon  its  under  side  this  skull  presents  a  number  of  points  of  interest.  The 
anterior  moiety  of  the  superior  mandible  is  here  seen  to  be  longitudinally  grooved 
by  a  broad  and  shallow  furrow,  which  gradually  becomes  somewhat  narrower  as  we 
proceed  backward,  to  finally  merge  into  the  convex,  median  portion  of  the  hinder 
half  of  this  great  rostrum.  Along  its  median  line  it  is  marked  by  a  few  scattered, 
slit-like  foramina  that  lead  into  its  shallow  interior,  which  latter  is  largely  filled  with 
an  open  mass  of  spongy,  osseous  tissue,  continuous  with  the  maxillo-palatines  behind. 

The  palatine  bodies,  including  their  heads,  fuse  together  for  their  entire  extent 
in  the  median  plane.  Resulting  from  this  union  we  have  a  single,  descending, 
median  carination,  composed  of  the  united  inner  keels  of  the  palatine  bodies  and  a 
similar  superior  median  one  composed  of  the  ascending  processes  of  the  same. 

The  latter  is  truncated  just  before  reaching  the  maxillo-palatine  bodies. 

This  skull  lacks  basi-pterygoid  processes,  while  the  pterygoids  themselves  are 
short,  thick  set  bones,  with  large  anterior  and  posterior  heads,  and  sharpened  longi- 
tudinal crests  on  the  superior  aspects  of  their  shafts. 

The  basi-temporal  triangle  is  small  and  its  area  concave.  A  thin,  pointed  lip  of 
bone  eaves  over  the  entrance  to  the  Eustachian  tubes,  which  are  here  apparently 
thoroughly  surrounded  by  bony  walls. 

We  find  the  foramen  magnum  situated  at  the  bottom  of  a  broad,  deep,  and 
transverse  concavity.  This  excavation  is  bounded  on  either  side  by  the  dome-like 
mastoid  prominences,  in  front  by  the  line  of  the  base  of  the  basi-temporal  triangle, 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  191 

and  behind  by  a  low,  smooth  ridge  which  arches  between  its  lateral  boundaries. 
The  foramen  magnum  cannot  be  seen  on  a  direct  vertical  view  of  the  base  of  the 
skull  (PL  XXVII.,  Figs.  35  and  36). 

The  occipital  condyle  is  rather  large,  ellipsoidal  in  form,  and  placed  transversely, 
while  the  outline  of  the  foramen  is  also  a  broad  ellipse,  but  with  its  long  axis  placed 
just  the  other  way.  The  plane  passing  through  its  periphery  makes  an  angle  with 
the  plane  of  the  basis  cranii  of  about  sixty  degrees. 

Regarding  this  skull  from  a  superior  aspect  we  are  to  note  the  small,  subcircular 
openings  to  the  nostrils,  situated  a  little  beyond  the  irregular  line  marking  the 
cranio-facial  hinge  (PI.  XXVII.,  Fig.  40). 

Their  centers  are  about  2  mm.  apart,  and  each  one  is  situated  at  the  posterior 
end  of  a  groove.  These  grooves  extend  the  entire  length  of  the  superior  mandible, 
passing  out  on  either  side  of  the  hook  at  its  anterior  extremity.  At  first  each  is 
rather  on  the  lateral  aspect  of  the  bone,  but  beyond  the  posterior  half  they  gradu- 
ally converge  and  get  on  top,  to  include  between  them  the  prominent  convex  cul- 
men.  Just  before  reaching  the  hook,  however,  the  included  surface  becomes  Mat 
and  depressed,  when  the  lines  terminate,  as  pointed  out  above. 

The  top  of  the  skull  in  this  Pelican  is  very  flat  for  the  frontal  region,  being 
simply  curved  downward  at  the  outer  borders.  As  we  proceed  backward  to  the 
parietal  region,  however,  it  gradually  becomes  more  convex  and  dome-like,  though 
still  retaining  its  absolutely  smooth  and  polished  character.  This  latter  may  also 
be  seen  from  a  posterior  aspect,  and  below  it  the  high,  arching,  and  equally  smooth 
occipital  area.  This  latter  extends  down  on  either  side  over  the  enormous  mas- 
toidal  elevations  of  this  bird.  We  also  notice  that  from  this  view  we  may  see 
directly  into  the  foramen  magnum  ;  the  entire  pterygoids  are  in  sight,  and  the  quad- 
rates come  down  far  below  the  basi-cranial  plane. 

The  mandible  from  the  skeleton  of  this  Pelican  is  represented  by  a  long,  narrow 
loop  of  bone,  which  is  strikingly  devoid  of  prominent  characters.  Its  symphysis  is 
very  short  and  decurved,  being  slightly  excavated  on  its  superior  aspect  behind  (PL 
XXVII.,  Fig.  41). 

The  upper  and  lower  margins  of  either  ramus  are  rounded  for  their  entire  length, 
while  the  sides  included  between  them  become  gradually  narrower  as  we  proceed  in 
the  direction  of  the  symphysis.  These  are  smooth  both  internally  and  externally 
and  both  concave  in  the  vertical  direction. 

Rather  more  than  the  posterior  moiety  of  each  ramus  is  hollow  for  the  admis- 
sion of  air,  and  each  presents  two  foramina,  which  seem  to  be  intended  for  that  pur- 
pose. One  of  these  is  on  the  inner  and  upper  aspect  of  the  ramal  shaft,  just  beyond 


192  MEMOIRS    OF   THE    CARNEGIE    MUSEUM 

a  concavity  that  occurs  immediately  anterior  to  the  articular  cup.  The  other,  ellip- 
tical in  form,  is  on  the  inner  and  lower  aspect,  and  about  2  cm.  beyond  it. 

Each  articular  cup  presents  two  concavities — a  central  one  and  another  occupy- 
ing the  inturned  process  of  this  extremity.  Both  have  pneumatic  foramina  at  their 
bases.  The  mandibular  angle  behind  is  truncate  and  much  compressed  in  the  per- 
pendicular direction.  The  under  surface  of  one  of  these  ends  is  perfectly  smooth 
and  gradually  merges  into  the  inner  and  outer  surface  of  the  ramal  shaft.  Almost 
complete  disappearance  of  the  coronoids  has  taken  place. 

Almost  the  entire  skull  of  this  bird  is  highly  pneumatic,  and  I  have  carefully 
compared  it  with  the  specimen  loaned  me  by  the  U.  S.  National  Museum,  and  find 
that  they  agree  in  all  essential  particulars.  In  the  latter  I  find  a  mandible  38  cm. 
long,  Avhile  the  symphysis  of  the  same  only  measures  4  mm.  The  superior  carina- 
tion  of  the  united  palatines  is  somewhat  higher,  especially  in  front  than  in  my  own 
specimen,  but  I  am  inclined  to  believe  that  in  mine  the  free  margin  has  somewhat 
broken  off,  and  due  allowance  should  be  made  for  it  in  the  figure  illustrating  the 
skull  of  this  bird  in  my  earlier  memoir  (Fig.  40)  showing  the  lateral  view  of  the 
Pelican's  skull,  when  the  supero-median  palatal  keel  is  drawn  a  little  too  low. 

Fig.  20  of  Huxley's  1867  paper  in  the  P.  Z.  S.  is  a  good  representation  of  the  pos- 
terior half  of  the  skull  of  a  pelican  (P.  onocrotalus)  seen  upon  its  basal  aspect.  The 
side  view  of  the  same  is  very  indifferently  drawn. 

Some  few  of  the  small  bones  of  the  disarticulated  National  Museum  specimen 
at  my  hand  may  have  been  lost,  but  none  of  any  consequence.  Almost  the  entire 
skeleton  is  pneumatic,  and  exceedingly  light.  The  pygostyle  is  as  light  as  a  wafer, 
and  taken  with  all  the  caudal  vertebne,  only  weighs  a  few  grains.  Among  the  non- 
pneumatic  bones  we  note  the  atlas,  the  fibulae,  the  first  metatarsal,  and  all  the  toe- 
joints.  Some  of  the  bones  are  actually  riddled  with  air-holes,  and  such  a  long  bone 
as  the  humerus  has  many  minute  foramina  at  very  various  localities  at  both  of  its 
extremities.  The  pelvis  weighs  no  more  than  were  it  made  of  cork,  and  so  it  is  with 
all  the  other  large  bones. 

Of  the  Remainder  of  the  Axial  Skeleton  in  Pelecanus. 

(See  Plate  XXVII.,  Figs.  31-34,  38,  39;  PI.  XXVIIL,  Fig.  42,  and  PI.  XXX., 

Fig.  49.) 

Professor  Mivart  found  in  the  spinal  column  of  a  specimen  of  Pelecanus  mitratus  in 
the  British  Museum  but  "forty  vertebne  in  all,  there  being  but  three  lumbar  and  five 
caudal"  ;  and  in  a  specimen  of  P.  onocrotalus  (No.  527A),  forty  one  vertebrse,  there 


SHUFELDT  :     OSTEOLOGY    OF    THE    STKGANOPODES  193 

being  but  three  sacro-caudals.     He  says,  however,  that  in  this  species  the  general 
number  seems  to  be  forty-two  vertebne  in  all,  not  counting  the  pygostyle. 

In  a  complete  skeleton  of  Pelecanus  fuscus  before  me  (No.  18483),  I  find  sixteen 
true  cervical  vertebrae,  none  of  which  support  true  ribs.  The  seventeenth  bears  a 
pair  of  large,  well-developed  ribs  which  do  not  connect  with  the  sternum,  and  which 
have  long  epipleural  appendages  low  down  on  their  shafts,  where  they  are  anchy- 
losed.  The  eighteenth  vertebra  is  the  ultimate  one  of  the  dorso-cervical  series  of 
the  spinal  column  that  is  free.  Its  ribs  are  broad  and  flat,  with  their  appendages' 
coossified  to  the  shafts  at  an  angle  of  45°,  and  inclined  to  be  slender,  narrow,  and 
pointed. 

The  nineteenth,  twentieth,  and  twenty-first  vertebra;  are  not  only  all  fused 
together,  but  are  similarly  joined  with  the  bones  forming  the  pelvic  "sacrum." 
This  union  is  most  perfect,  and  is  considerably  fortified  by  the  complete  coossification 
of  the  metapophyses  extending  between  the  extremities  of  the  transverse  processes, 
and  then  with  anterior  iliac  borders,  in  which  location  the  ossifying  process  has  been 
extended  quite  across,  thus,  on  superior  aspect,  shutting  the  twenty-first  vertebra 
out  from  view. 

These  three  vertebrte  also  bear  broad  and  flat  ribs,  connecting  with  the  sternum 
as  do  all  the  thoracic  ribs  in  this  Pelican.  This  pair  belonging  to  the  nineteenth 
vertebra  are  quite  like  those  described  above  for  the  eighteenth  ;  they  are  broader, 
however,  which  is  also  the  case  with  the  pair  suspended  from  the  twentieth  vertebra. 
These  last  have  the  epipleural  spines  reduced  in  size,  while  the  last  two  pairs  of 
ribs,  or  those  belonging  to  the  twenty-first  vertebra,  and  the  pair  of  "pelvic  ribs" 
lack  these  appendages  entirely. 

Almost  completely  pneumatic  in  character,  the  leading  costal  ribs  are  rather  short, 
but  the  series  gradually  increases  in  length  as  we  pass  backwards,  all  of  them  being 
more  or  less  pneumatic,  and  all  being  remarkable  for  having  their  extremities 
enlarged,  for  the  purpose  of  affording  a  greater  articulatory  surface  at  those  points. 
For  the  most  part,  the  pneumatic  foramina  in  these  hremapophyses  are  to  be  found 
at  their  sternal  ends. 

The  free  pelvic  vertebra?  all  have  a  swelled  appearance,  while  their  surfaces  are 
as  a  rule  smooth,  their  salient  angles  much  rounded  off,  and  their  processes  quite 
subordinated. 

The  cup  of  the  atlas  is  deeply  notched  above,  as  is  the  articular  surface  of  the 
body  behind,  concaved  upon  the  same  aspect.  This  surface  is  of  an  elongo-reniform 
outline,  its  transverse  diameter  being  of  the  greatest  length.  A  small  hypopophysial 
tip  extends  backwards  from  its  mid-point  below. 


194  MEMOIRS   OF   THE    CARNEGIE    MUSEUM 

Not  especially  stout,  the  lateral  pedicels  support  a  broad,  oblong  neural  arch, 
which  has  a  straight  anterior,  and  a  concave  posterior  margin.  Air  gains  access  to 
this  vertebra  through  some  holes  situated  in  or  near  a  small  concavity,  over  which 
articulates  the  ventral  surface  of  the  odontoid  process  of  the  axis  when  the  bones 
are  in  situ.  A  polishing  of  the  surface  alone  indicates  the  points  where  the  ante- 
rior margin  of  the  neural  arch  comes  in  contact  with  the  occipital  bone  of  the 
cranium,  and  where  the  ventral  aspect  of  its  posterior  margin  rides  on  the  upper 
part  of  the  anterior  margin  of  the  neural  canal  of  the  axis. 

A  broad-based,  swollen,  and  tuberous  neural  spine  is  one  of  the  chief  characters 
of  the  last-named  vertebra,  while  its  bpemal  spine,  situated  posteriorly  on  the  centrum, 
is  transversely  compressed,  sharp  along  its  infero-mesial  border,  and  withal  rather 
inconspicuous. 

The  articular  surface  on  the  body  for  the  atlas  is  deeply  concave,  and  always 
presents  a  large  mesial  pneumatic  foramen  at  its  base,  just  beneath  the  odontoid 
process.  Posteriorly,  the  neural  arch  of  this  vertebra  far  overhangs  the  centrum 
below,  while  either  postzygapophysial  portion  of  it,  not  strictly  defined  from  the 
bone,  has  upon  its  direct  ventral  aspect  a  large  oval  articular  facet  for  articulation 
with  the  corresponding  ones  at  the  prezygapophyses  of  the  third  vertebra. 

We  have  no  lateral  canals  in  the  axis  vertebra  of  this  Pelican,  but  a  small  pneu- 
matic foramen  is  usually  seen  on  either  side,  at  the  site  of  their  occurrence  in  the 
next  bone  of  the  spine  behind  it,  at  points  where  they  open  posteriorly.  In  the 
third,  fourth,  fifth  and  sixth  vertebra  the  neural  spine  is  represented  by  a  low, 
lengthy,  and  thickened  ridge,  which  fails  in  any  case  to  reach  the  dorsal  margins  of 
the  neural  canal,  either  in  front  or  behind.  In  the  seventh  vertebra  the  neural 
spine  is  much  restricted,  occupying  only  the  center  of  the  bone.  It  begins  to  dis- 
appear in  the  eighth  ;  is  almost  absent  in  the  ninth  and  tenth  ;  feebly  reappears  in 
the  eleventh  and  twelth ;  begins  to  be  tuberous  in  the  thirteenth ;  and  from  this 
on  it  slowly  assumes  the  form  it  has  in  the  dorsal  series,  where  it  is  low,  thickened, 
and  wedge-shaped,  with  base  behind  and  apex  in  front. 

Far  back  on  the  centrum  of  the  third  vertebra  we  find  a  short,  thick,  and  low 
heemal  process  ;  somewhat  resembling  the  one  on  the  axis.  The  character  is  quite 
obliterated  in  the  fourth  vertebra,  where  we  begin  to  see,  anteriorly  beneath  the 
extreme  fore  part  of  the  centrum,  the  first  indications  of  the  formation  of  the  carotid 
passage.  They  are  more  distinct  in  the  fifth  vertebra ;  still  more  so  in  the  sixth  ; 
decidedly  so  in  the  seventh,  where  the  remarkable  peculiarity  exists  in  that  a  carotid 
channel  with  thin,  conspicuous  side-walls  abruptly  develops  at  the  extreme  hinder 
end  of  the  centrum.  This  character  is  just  as  well  marked  in  the  eighth  vertebra, 


SHTJFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  195 

after  which  it  gradually  disappears  (never  to  form  a  completed  tube),  to  be  gone 
entirely  in  the  thirteenth  cervical. 

In  the  eighth  vertebra  the  anterior  part  of  the  carotid  passage  is  a  solid,  closed 
tube,  its  parapophysial  walls  being  thick  and  strong,  the  passage  of  considerable 
caliber,  and  the  whole  occupying  more  than  the  anterior  third  of  the  ventral  aspect 
of  the  bone.  It  also  shows,  ventrad,  a  mid-longitudinal  ridge,  with  a  longitudinal 
gutter  upon  either  side  of  it.  This  carotid  canal  remains  a  closed  tube  to  include 
the  fourteenth  vertebra,  slowly  changing  in  character  as  we  near  the  dorsal  series. 
In  the  fifteenth  to  the  seventeenth  inclusive,  its  place  is  taken  by  a  well-marked 
haemal  spine  —  a  character  entirely  absent  in  the  eighteenth  vertebra,  which  is  a  true 
dorsal  one. 

No  evidence  of  a  haemal  spine  whatever  exists  in  the  three  fused  dorsal  vertebrae, 
and  in  them  the  neural  spine  is  but  represented  by  a  coossified,  flattened  ridge, 
hardly  at  all  higher  than  the  fused  metapophysial  track  at  the  ends  of  the  dia- 
pophyses,  on  either  hand.  Lateral  canals  begin  in  the  third  vertebra  and  persist  to 
the  sixteenth  inclusive.  They  are  long  and  of  small  caliber  in  the  third,  fourth, 
fifth  and  sixth,  materially  shortened  in  the  seventh  ;  somewhat  more  so  in  the 
eighth,  where,  for  the  first  time,  their  anterior  opening  looks  directly  dorsad,  which 
latter  continues  to  be  the  case  in  the  ninth,  tenth,  eleventh,  twelfth,  thirteenth 
and  fourteenth,  the  canals  increasing  in  caliber,  but  at  the  same  time  shortening  in 
length  as  we  pass  through  the  series  just  named.  In  the  fifteenth  and  sixteenth 
vertebrae,  the  lateral  canals  are  parallel  with  the  neural  canal,  about  one  third 
smaller  in  size,  their  ventral  floors  being  formed  by  the  pleura  pophysial  elements. 
For  the  most  part  the  comparatively  rather  small  neural  canal  is  subcylindrical  in 
form,  being  most  compressed  vertically  as  we  pass  towards  the  distal  cervicals,  to 
become  more  cylindrical  again  in  the  ultimate  free  dorsal.  After  passing  the  fourth 
cervical,  and  from  thence  on  to  include  the  sixteenth,  this  tube  is  markedly  of 
greater  caliber  behind  than  it  is  in  front,  in  any  single  vertebra  of  this  part  of  the 
spinal  column. 

This  character  can  be  particularly  well  seen  in  the  eleventh  cervical.  Through- 
out, the  parapophysial  styles  are  very  short.  On  the  third  vertebra  they  are  far 
apart,  but  gradually  approach  each  other  and  the  median  line  to  include  the  sixth 
cervical.  Their  character  changes  in  the  seventh,  where  they  become  sharp,  short, 
and  spiculiform.  In  the  eighth,  ninth  and  tenth  they  are  represented  by  mere 
spinelets,  close  together  mesiad  and  are  to  be  found  on  the  postero-ventral  border 
of  the  carotid  canal.  From  this  on  they  gradually  separate  again,  and  entirely 
disappear  from  the  ultimate  cervical  vertebrae. 


196  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

The  prezygapophysial  facets  are  long,  narrow  and  ellipsoidal  in  form  on  the 
third  cervical,  being  considerably  nearer  each  other  at  their  posterior  ends  than  they 
are  in  front.  They  face  almost  directly  dorsad.  As  we  pass  to  include  the  seventh 
cervical  these  facets  gradually  become  more  and  more  circular  in  outline,  and  incline 
to  face  towards  the  median  plane.  This  they  do  quite  abruptly  in  the  eighth 
cervical  —  distinctly  so  in  the  ninth,  look  slightly  backwards  in  the  tenth,  but 
again  thereafter  gradually  right  themselves  so  as  to  once  more  face  the  median 
plane.  Here  it  will  be  seen  we  have  the  same  arrangement  noted  for  the  Cormor- 
ant and  the  Anhinga  though  not  nearly  so  well  marked.  The  postzygapophyses 
are  short  and  stumpy  in  the  fourth  vertebra,  but  very  gradually  lengthen  to  include 
the  twelfth  cervical,  after  which  they  once  more  shorten,  to  become  short  and 
thick-set  again  in  the  last  cervicals,  and  the  free  dorsal,  in  which  last — as  distinct 
processes  —  they  are  practically  aborted.  Their  facets  for  articulation  with  the  cor- 
responding ones  on  the  prezygapophyses,  are  upon  their  ventral  aspects,  and  of 
course  have  an  exact  counter-facing  to  them. 

These  vertebras  commence  to  lengthen  after  passing  the  third  cervical,  becoming 
quite  longish  and  narrow  in  mid-series — they  then  very  gradually  assume  the 
broad,  massive,  and  short  type  found  at  the  end  of  the  cervical  chain  and  in  the 
free  dorsal.  Though  these  latter  are  large  they  agree  with  all  the  others  of  the 
column,  from  their  extreme  pneumaticity,  in  being  very  light  in  weight. 

The  three  last  dorsal  vertebrae  coossify,  or  rather  in  the  adult  Pelican  are  fused 
with  those  of  the  pelvic  sacrum,  and  the  leading  vertebra  of  the  latter  is  quite 
similar  to  one  of  the  last  dorsals,  but  in  the  next  three  the  parapophysial  processes 
are  thrown  up  against  and  completely  fused  with  the  ventral  surfaces  of  the  ilia 
upon  either  side.  These  processes  are  spine-like  and  nearly  aborted  in  the  next 
following  one,  while  in  the  next  three  they  are  absent  entirely.  This  is  well  shown 
in  the  pelvis  of  Pelecanus  sharpei  (PI.  XXX.,  Fig.  49). 

Then  comes  a  true  sacral  vertebra,  which  has  them  long  and  well-developed, 
reaching  out  to  points  posterior  to  the  acetabute  where  they  fuse  and  broaden,  and 
otherwise  develop  bone  which  greatly  strengthens  the  pelvis  in  all  this  vicinity. 
The  five  remaining  vertebrae  of  the  "pelvic  sacrum"  also  possess  parapophysial  proc- 
esses, which  with  the  diapophyses  above  them,  most  completely  coossify  with  the 
internal  borders  of  the  ilia  upon  either  hand.  Of  good  capacity,  the  "  pelvic  basin  " 
is  of  a  short,  oblong  form,  being  one  third  narrower  than  it  is  long,  and  of  nearly 
uniform  depth  throughout.  Viewed  laterally,  we  find  the  acetabulum  to  be  large 
and  circular;  its  internal  periphery  coequal  with  its  external  one.  Above  it  is  a 
fair-sized  antitrochanter,  facing  forward  and  downward,  and  very  slightly  outward. 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  197 

The  obturator  foramen  merges  completely  with  the  obturator  space,  which  latter  is 
large  and  broadly  spindle-form  in  outline.  No  prepubis  is  present,  and  the  post- 
pubic  style  is  curved  and  very  slender  until  it  comes  in  contact  at  a  point  on  the 
postero-ventral  angle  of  the  ischium,  after  which  it  is  turned  slightly  mesiad  and 
somewhat  though  not  at  all  greatly  enlarged. 

An  extensive,  subelliptical  ischiadic  foramen  monopolizes  much  space  on  this  lat- 
eral aspect  of  the  pelvis.  Behind  it  the  surface  of  the  bone  is  smooth,  and  finally 
we  notice  a  broad,  shallow  notch  on  the  posterior  border,  between  ilium  and  ischium. 
Dorsad,  the  pelvis  is  broad,  smooth  and  flat,  with  a  thorough  fusing  of  all  the  bones 
composing  it.  Parial  foramina  occur  between  the  diapophyses  of  the  uro-sacral  ver- 
tebras only  in  the  post-acetabular  region,  where  they  are  of  good  size. 

The  ultimate  vertebra  may  be  more  or  less  individually  outlined,  and  simulate 
in  form  the  leading  one  of  the  caudal  series.  In  the  pre-acetabular  region  the  ilia 
are  moderately  concaved,  lie  more  or  less  in  the  horizontal  plane,  and  fail  to  come 
quite  in  contact  with  each  other  over  the  "sacral  crista,"  which  latter  is  here  quite 
low  and  indistinct,  due  to  the  thorough  fusing  of  all  the  bones  in  this  region.  From 
the  extreme  outer  point  of  one  antitrochanter  to  the  corresponding  point  on  the 
same  process  on  the  other  side  measures,  on  a  right  line,  about  7.5  cm.,  while  the 
length  of  the  "  pelvic  sacrum"  is  about  12  cm. 

Thus,  though  steganopodous  in  character,  this  pelvis  of  Pelccanus  differs  mate- 
rially in  form  and  aspect  from  the  pelvis  of  either  a  Cormorant  or  an  Anhinga. 

In  the  skeleton  of  the  tail  we  find  six  free  caudal  vertebrae  and  a  large  pygostyle. 
All  are  highly  pneumatic.  The  neural  canal,  of  some  considerable  size,  passes 
through  the  entire  series  and  well  into  the  pygostyle — an  unusual  occurrence  in 
birds.  All  possess  tuberous  neural  spines,  but  only  the  last  three  have  haemal  ones, 
and  these  increase  in  size  from  the  last  caudal  to  include  the  fourth.  They  extend 
almost  directly  forwards.  The  transverse  processes  of  the  first  five  vertebra*  are 
bent  ventral-wise,  more  particularly  in  the  second  and  third,  while  in  the  last  one 
they  are  nearly  aborted.  The  articular  facets  on  the  centra  are  concaved  anteriorly, 
and  nearly  flat  on  the  posterior  aspects. 

The  large  pygostyle  is  drawn  out  into  a  blunt  point  at  its  postero-superior  angle. 
Its  dorsal  margin  and  the  hinder  half  or  more  of  its  ventral  margin  are  sharp  —  the 
remainder  of  the  latter  being  thickened.  The  antero-inferior  angle  projects  forwards, 
corresponding  to  the  haemal  spine  of  the  first  vertebra  absorbed  to  form  this  com- 
pounded bone. 

Thus  it  will  be  seen  that  in  this  species  of  Pelican  we  have  41  vertebrae  in  its 
spinal  column,  namely :  sixteen  cervicals  that  are  without  free  ribs;  one  cervical  with 


198  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

well-developed  ribs ;  one  free  dorsal  ;  three  dorsals  fused  with  the  pelvic  sacrum ; 
fourteen  in  the  pelvic  sacrum ;  and  six  caudals ;  the  pygostyle  not  being  included 
in  this  count. 

The  sternum  and  os  furcula  are  intimately  fused  together  at  the  carinal  angle, 
forming  there  an  extensive  union.  This  is  also  the  case  in  Pelecanus  sharpei  (PI. 
XX  VI 1 1.,  Fig.  42).  Apart  from  this  fact,  the  sternum  has  much  about  it  to  remind  us 
of  that  bone  in  Plialacrocorax.  It  is  profoundly  concave  upon  its  dorsal  aspect,  and 
correspondingly  convex  upon  the  opposite  surface.  Either  costal  border,  trans- 
versely very  broad,  is  occupied  nearly  its  entire  length  by  the  five  hsemapopliysial 
facets,  with  the  long,  shallow  concavities  that  are  between  them.  These  latter  are 
riddled  with  small  pneumatic  foramina,  while  only  a  few  of  these  openings  are  found 
elsewhere  in  the  sternum,  and  they  are  very  minute.  Two  wide,  shallow  indenta 
tions  mark  the  xiphoidal  margin,  and  the  lateral  xiphoidal  processes  are  short  with 
rounded  ends.  They  extend  backwards  and  outwards.  The  deep  keel  projects 
somewhat  forwards,  but  is  merged  upon  the  surface  of  the  bone  behind  long  before 
it  reaches  the  posterior  sternal  margin. 

Each  "costal  process"  is  low  and  of  a  subquadrilateral  outline.  On  the  anterior 
border  of  the  bone  there  is  a  notable  concavity,  longitudinally  disposed  and  of  some 
considerable  breadth.  It  extends  from  the  upper  termination  of  the  anterior  and 
rather  sharp  margin  of  the  keel  to  lead  into  the  general  concavity  of  the  dorsal  as- 
pect of  the  sternal  body.  It  separates  the  long,  narrow  costal  grooves  in  front,  as 
well  as  the  rather  deep  costal  facets  above  them. 

U-shaped  in  pattern,  the  lower  loop  of  the  os  furcula  is  not  particularly  stout, 
while  the  chief  feature  of  this  bone  is  its  enormously  swelled  and  enlarged  free 
upper  extremities  (PI.  XXVIII.,  Fig.  42). 

These  are  entirely  hollow,  and  each  is  provided  with  an  elongated  pneumatic 
foramen  upon  its  postero-mesial  aspect.  Postero-laterally,  either  one  presents  for 
examination  a  subcircular  facet  for  articulation  with  the  head  of  the  corresponding 
coracoid,  internal  to  which  a  stumpy,  tuberous  projection  extends  backwards.  But 
this  fails  by  an  extensive  interval  to  meet  the  scapula,  when  the  bones  of  the 
shoulder-girdle  are  articulated  as  in  life.  The  mesial  and  outer  aspects  of  these 
great  clavicular  heads  are  flat  and  smooth  ;  anteriorly,  their  thickened  borders  are 
convex  from  above  downwards,  the  posterior  borders  being  concave.  On  top  they 
each  present  a  flat,  triangular  surface  with  the  apex  to  the  front. 

From  its  extreme  pneumaticity  I  find  a  coracoid  in  Pelecanus  fuscus  to  be  a  very 
light  bone,  while  it  has  an  altitude  of  9.7  cm.,  being  large  in  its  other  proportions. 
The  sternal  end  is  considerably  dilated,  and  to  the  other  side  is  a  very  small  up- 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  199 

turned  epicoracoidal  process.  On  the  posterior  side  at  the  mesial  angle  there  is  a 
prominent  jutting  flange  bearing  an  articular  facet  upon  its  entire  under  surface  for 
articulation  with  the  sternum.  The  inner  two  thirds  of  the  inferior  border  is  also 
for  articulation  with  the  same  bone.  The  head  is  more  or  less  massive,  being  ob- 
liquely compressed  above.  Well  below  this,  anteriorly,  is  a  non-elevated,  circular 
facet  for  the  os  furcula.  Above  the  large  glenoid  concavity,  between  it  and  the 
summit  of  the  bone,  is  a  deep  valley  passing  downwards  and  forwards  from  the  pos- 
terior aspect.  Pneumatic  foramina  occur  in  it,  as  they  do  also  on  the  mesial  aspect 
of  the  shaft  in  an  elongated  group  below  the  coracoidal  head.  The  facet  for  the 
articulation  with  the  scapula  is  a  deep  circumscribed  concavity,  and  in  front  of  it  a 
conspicuous  scapular  process  is  developed,  but  it  never  reaches  the  os  furcula  in 
articulation  when  the  bones  are  in  situ.  Below  the  open  valley  for  the  tendons, 
the  shaft,  is  pierced  by  a  foramen,  a  character  often  seen  in  birds  of  other  groups. 

A  scapula  is  small  in  proportion  for  the  size  of  the  bird,  thick,  narrow  and 
short.  It  is  bent  neither  right  nor  left,  but  moderately  curved,  its  convexity  being 
along  its  dorsal  aspect.  It  has  a  distinct  ellipsoidal  raised  facet  for  articulation  with 
the  above-described  pit  in  the  coracoid,  while  the  surface  it  offers  for  the  glenoid 
cavity  is  small.  Its  most  striking  character  is  the  very  much  elongated  process  at  its 
antero-mesial  angle.  This  acromial  process  does,  not  meet  the  clavicle  in  articula- 
tion. On  the  dorsal  aspect  of  the  blade,  near  its  middle,  is  a  distinct  tubercle  for 
muscular  attachment,  that  is  quite  noticeable. 

Of  the  Appendicular  Skeleton. 
(See  Plate  XXVIL,  Figs.  31-34,  38  and  39.) 

In  the  pectoral  limb  the  humerus  is  a  very  long,  large  bone  showing  the  usual 
double  sigrnoidal  curvature  in  its  shaft,  which  for  its  middle  third  is  subcylindrical 
in  form.  (See  PL  XXVIL,  Fig.  34.) 

The  radial  crest  is  but  moderately  developed,  while  a  peculiar  tuberous  enlarge- 
ment is  found  on  the  ulnar  border  of  the  bone,  just  distad  to  the  pneumatic  cavity. 
It  is  stopped  abruptly  immediately  before  we  come  to  the  shaft,  by  a  distinct 
though  very  narrow  notch.  The  ulnar  tuberosity  is  not  very  prominent,  only  parti- 
ally overhanging  the  pneumatic  fossa.  Between  it  and  the  true  humeral  head  is  a 
distinct  notch  or  valley.  At  the  distal  end  of  the  shaft,  the  oblique  and  radial 
tubercles  stand  out  with  considerable  prominence  ;  the  olecranon  fossa  is  pretty  well 
marked,  otherwise  we  find  only  the  usual  ornithic  characters  here.  The  humerus 
has  an  extreme  length  of  about  27  centimeters. 


200  MEMOIRS    OF   THE   CARNEGIE    MUSEUM 

The  ulna  of  the  forearm  is  even  much  longer  than  this,  being  fully  32.5  centi- 
meters in  length,  and  from  its  great  pneumaticity  a  very  light  bone.  At  its  proxi- 
mal extremity  it  has  a  very  large  pneumatic  fossa  just  below  the  facet  for  articulation 
with  the  radius.  The  olecranon  process  is  barely  at  all  developed.  Along  the 
moderately  curved  shaft  there  are  at  least  twenty-two  distinct  papillae,  nearly  equi- 
distant from  each  other,  for  the  insertion  of  the  quill-butts  of  the  secondary  feathers 
of  the  wing.  On  section,  at  its  middle  third,  the  shaft  is  triangular,  and  its  distal 
end  presents  us  with  nothing  peculiar.  (The  ulna  of  P.  sharpei  is  shown  in  PI. 
XXVIL,  Fig.  31.) 

The  radius  is  a  long,  slender  bone  and  is  also  somewhat  curved.  Its  distal  end 
is  transversely  expanded,  below,  which  expansion  is  the  pneumatic  fossa, 

The  radiale  and  ulnare  of  the  carpus  both  plainly  show  the  pneumatic  fossa 
leading  into  them,  as  do  all  the  bones  of  the  manus.  The  carpo-metacarpus  has 
an  extreme  length  of  about  12.4  centimeters.  Along  its  continuity  it  is  slightly 
carved  anconad,  while  the  very  slender  medius  metacarpal  stands  well  away 
from  the  main  shaft,  being  somewhat  longer  than  it  is  at  the  point  of  anchy- 
losis distally.  The  pollex  metacarpal  is  short  and  bulky.  The  carpo-metacarpus  of 
P.  sharpei  exhibits  the  usual  characters  of  this  bone  among  the  Pelicans  (PI. 
XXVIL,  Fig.  39). 

The  proximal  phalanx  of  the  index  digit,  with  a  length  of  5  centimeters  has 
a  broad  expansion  posteriorly,  and  is  peculiar  in  being  perfectly  flat  and  smooth 
upon  its  anconal  side,  while  upon  the  palmar  aspect  it  is  divided  into  two 
deep  concavities  which  are  absolutely  riddled  with  pneumatic  foramina  at  their 
bases. 

The  terminal  joint  of  this  finger  is  long  and  trihedral  in  form,  with  its  pneu- 
matic foramen  at  the  proximal  end.  Though  a  little  longer  than  the  pollex 
phalanx,  the  latter  has  very  much  the  same  shape,  and  is  likewise  pneumatic.  The 
free  terminal  joint  of  the  medius  digit  has  a  broadish,  triangular  expansion  behind, 
and  the  holes  for  the  admission  of  air  pierce  it  upon  both  sides.  This  bone  is  3.4 
centimeters  long,  by  1.3  broad  at  its  broadest  part ;  while  the  distal  joint  of  index 
has  an  extreme  length  of  4.6  centimeters. 

In  the  pelvic  limb,  a  femur  although  pneumatic  to  a  certain  degree,  it  is  not  so 
markedly  so,  as  either  the  tibio-tarsus  or  the  tarso-metatarsus.  It  will,  in  the  dried 
skeleton,  probably  weigh  more  than  the  former,  notwithstanding  it  is  not  as  large, 
nor  so  long.  Its  stout  shaft  is  but  very  little  bowed  in  the  antero-posterior  direction, 
and  the  extremities  are  large  and  massive.  The  broad  trochanter  does  not  rise  above 
the  articular  summit  of  the  bone  proximally,  and  the  pit  for  the  round  ligament  on 


SHUFELDT  :     OSTEOLOGY    OF   THE    STEOANOPODES  201 

the  caput  femoris  is  but  little  excavated.  Distally,  the  condyles,  •  appear; 'to' -bp 
somewhat  antero-posteriorly  compressed,  and  transversely  spread  apart  from  each 
other.  The  external  condyle  is  slightly  the  lower  and  larger  of  the  two,  and 
it  is  deeply  cleft  behind  for  the  head  of  the  fibula.  Anteriorly,  the  rotular  chan- 
nel is  shallow,  nor  is  the  popliteal  fossa  on  the  other  side  of  the  bone  as  deep  in 
proportion  as  we  find  it  in  many  other  birds,  both  large  and  small,  (PI.  XXVII., 
Fig.  32). 

A  tibio-tarsus  instead  of  being  bowed  in  the  antero-posterior  direction  as  it  often 
is,  it  curves  the  other  way  so  that  the  fibular  border  of  the  bone  is  con  vexed,  and 
the  opposite  one,  correspondingly,  or  even  rather  more,  concaved.  The  extremities 
are  large,  but  the  several  cnemial  processes  at  the  proximal  one  are  but  very  moder- 
ately developed.  Low  and  long,  the  fibular  ridge  extends  down  half  the  length  of 
the  shaft,  and  its  articular  margin  or  border  is  roughened.  The  tibio-tarsus  of  P. 
sharpei  exhibits  these  characters  very  well,  as  they  are  seen  in  the  Pelecanidse 
generally  (PI.  XXVII.,  Fig.  33). 

At  the  distal  end  of  the  tibio-tarsus,  the  large  condyles  of  the  usual  reniform  out- 
line, protrude  prominently  to  the  front,  while  behind  they  almost  immediately 
merge  into  the  general  surface  of  the  lower  end  of  the  shaft.  The  intercondylar 
interval  is  deeply  excavated  between  them  in  front ;  at;their  lateral  aspects  the  points 
for  tendinal  and  ligamentous  insertion  are  roughened  and  distinctly  defined.  A 
small  bony  bridge,  such  a  frequent  ornithic  character,  spans  obliquely  the  anterior, 
longitudinal  channel  for  the  passage  of  tendons.  In  the  deepest  part  of  this  recess, 
and  directly  under  this  little  osseous  bridge,  a  large  pneumatic  foramen  enters  the 
shaft  of  the  bone.  It  is  the  principal  aperture  of  this  kind,  by  far,  in  the  bone,  and 
exists  in  the  same  place  in  the  shaft  of  the  fellow  of  the  opposite  side. 

A  fibula  has  its  head  and  articular  surface  thereon  moderately  well  developed, 
but  the  bone  contracts  rapidly  as  we  proceed  in  the  direction  of  its  distal  end,  and 
after  passing  the  articular  surface  for  the  tibia,  it  comes  to  be  little  more  than  a 
stout,  bony  thread,  that  by  np  means  reaches  the  condyle  of  the  tibio-tarsus,  nor 
does  it  anchylose  with  its  distal  end. 

Pelicans  have,  comparatively  speaking,  a  very  small  patella,  which  is  roughly 
wedge-shaped  in  form,  with  the  flat  base  below,  and  the  superior  edge  rounded,  and 
not  especially  sharp. 

The  torso-metatarsus  is  a  stout,  straight  bone,  with  pronounced  characteristics.  The 
intercondyloid  process  upon  its  summit  is  rounded  and  conspicuous.  Immediately 
below  it,  in  front,  terminates  the  usual  longitudinal  channel  found  on  the  anterior 
aspect  of  the  shaft.  It  is  deep  here  and  opens  into  the  shaft  by  a  double  pneu- 


202     ;  :  ;  t  '  MEMOIRS  OF  THE  CARNEGIE  MUSEUM 


;  ;  for'anjen  J-  The  inner  one  of  these  is  large,  and  not  only  communicates  with 
ine  interior  of  the  shaft  but  passes  also  directly  through  it  —  appearing  to  the  inner 
side  of  the  base  of  the  hypotarsus  as  a  large  foramen.  Two  or  three  much  smaller 
foramina  appear  upon  the  opposite  side  of  the  hypotarsus,  and  they  lead  to  similar 
passages  through  the  shaft. 

A  prominent  feature  of  this  bone  is  its  large  hypotarsal  process.  This  is  com- 
posed of  a  thick,  oblong  piece  or  internal  portion,  which  is  capped  upon  its  posterior 
aspect  by  an  elliptical,  vertical  cap,  having  slightly  protruding  margins. 

Two  very  much  smaller  such  plates  are  developed  external  to  this  larger  one, 
having  each  only  about  one  half  its  altitude,  and  being  not  more  than  one  fourth  as 
thick.  By  their  posterior  surfaces  more  or  less  ossifying  across,  two  vertical  tubes 
are  formed,  an  internal  and  external  one,  through  which  the  tendons  pass  in  life. 
As  thus  formed,  this  hypotarsus  stands  out  rather  abruptly  and  perpendicularly 
from  the  shaft,  with  hardly  any  inclination  to  merge  with  it  at  its  lower  part,  as  is 
the  case  in  a  good  many  birds.  As  to  the  shaft  of  this  bone,  it  is  convex  posteriorly 
and  strongly  marked  by  the  raised  muscular  lines  ;  it  is  concaved  slightly  in  front, 
the  excavation  being  very  deep  proximally  ;  shallow  in  the  middle  third  ;  and  deep- 
ening a  little  again  as  it  passes  into  the  usual  foramen  between  and  above  the  external 
and  middle  trochlear  processes.  These  latter  are  large  and  normally  disposed,  the 
mid  one  being  the  lower  of  the  three,  while  the  internal  and  external  project  about 
equally  backwards.  The  facet  for  the  free  first  metatarsal  is  concave  and  of  some 
considerable  size.  The  os  metatarsale  accessorium  is  a  little  over  two  centimeters  long, 
presenting  the  usual  head  and  being  slightly  twisted  upon  itself  distad.  It  agrees 
with  the  toe-joints  in  being  non-pneumatic.  These  latter  are  nearly  all  straight, 
only  some  of  the  distal  ones  being  slightly  curved.  For  a  bird  as  large  as  a  Pelican 
they  indicate  rather  a  feeble  foot,  and  this  is  further  sustained  when  we  come  to  see 
the  weak  terminal  joints,  which  are  ti'ansversely  somewhat  compressed,  not  very 
long,  but  withal  distinctly,  in  fact  rather  strongly  curved.  These  phalangeal  joints 
are  arranged  upon  the  plan  of  2,  3,  4,  and  5  bones  to  the  hallux,  second,  third  and 
fourth  toes  respectively. 

Pelecanus  fuscas  has  a  femur  8.5  cm.  long;  a  tibio-tarsus  of  12.5  cm.;  a  tarso- 
metatarsus  of  7.8  cm.  and  a  mid-anterior  basal  phalanx  of  pes  of  about  3.9  cm.  in 
length. 

When  one  comes  to  think  of  it  then,  a  Pelican  has  rather  a  peculiarly  balanced 
skeleton.  Its  lower  jaw  is  considerably  longer  than  its  ulna,  and  the  latter  is  in  turn 
considerably  longer  than  the  humerus.  This  last-named  bone  is  only  a  little  more 
than  half  as  long  as  the  carpo-metacarpus  of  manus.  The  tibio-tarsus  and  the  carpo- 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  203 

metacarpus  are  almost  exactly  of  a  length,  the  difference  being  only  a  millimeter  in 
favor  of  the  former.19 

Further  information  in  regard  to  the  osteology  of  the  Pelecanidee  will  be  given 
later  on  in  the  present  memoir,  as  well  as  in  the  explanation  of  plates  at  its  close. 
In  Volume  I.  of  the  Hand-List  of  Birds  by  Dr.  R.  Bondler  Sharpe  (1899,  pp.  238, 
239),  I  find  that  he  recognizes  ten  species  of  existing  Pelicans,  and  seven  fossil 
ones.  They  are  found  in  nearly  all  parts  of  the  world,  including  Australia,  Tas- 
mania and  New  Guinea.  It  is  not  likely  that  they  differ  very  widely  in  their 
osteology,  and  it  is  probable  that  in  its  main  features  it  is  very  well  exemplified  in 
Pelecanus fuscus  as  has  just  been  set  forth  above. 

Existing  Pelicans  have  by  ornithologists  generally,  all  been  restricted  to  the  one 
genus  Pelecanus  of  the  family  Pelecanidas,  where  they  undoubtedly  belong. 

On  the  Skeleton  of  Fregata. 

(See  Plate  XXIX.,  Figs.  45-48 ;  PI.  XXX.,  Figs.  50,  51.) 

Of  all  the  steganopodous  birds  perhaps  no  one  of  them  exceed  Fregata  aquila,  in 
point  of  interest,  in  so  far  as  its  osteology  is  concerned.  In  not  a  few  particulars  it 
has  a  very  remarkable  skeleton,  while  in  others  it  would  appear  to  indicate  that  the 
form  or  species  is  a  more  or  less  generalized  one.  For  example,  both  superficially 
and  otherwise,  the  skull  of  Fregata  resembles,  in  not  a  few  respects,  the  skull  in  some 
species  of  Albatrosses  (Diomedeidse).  This  not  only  applies  to  the  lower  jaw,  where 
the  similarity  is  very  evident,  but  also  to  a  number  of  characters  in  the  cranium 
and  face.  The  long,  powerfully  hooked  superior  mandibles  are  a  good  deal  alike, 
as  are  the  maxillo-palatines.  Fregata  has  a  vomer  that  approaches  that  bone  in  the 
Albatrosses ;  its  palatines  are  not  far  off,  and  even  still  less  so  its  pterygoids  and 
quadrates.  The  lacrymals  are  upon  the  same  plan  of  structure,  and  the  entire 

19  There  are  some  specimens  of  embryos  and  subadults  both  of  Pelecanus  and  Cormorants  in  the  U.  S.  National 
Museum  collections,  and  at  my  request  Mr.  Lucas  has  examined  some  of  these  for  me,  and  writes  the  following  letter 
on  the  subject,  for  all  of  which  it  gives  me  pleasure  to  thank  him. 

DEAR  DK.  SHUFELDT  : 

I  have  examined  Pdecanus  sp.  about  three  or  four  days  old  and  Phalacrocorax  carunculatus  for  supramaxillary  and 
found  no  trace  in  either.  Pelecanus  seems  to  mature  more  rapidly  than  Phalacrocorax.  In  tl)e  young  Pelican  the  lacry- 
mal  is  well  developed  and  free,  and  there  is  no  trace  of  the  partial  hinge  joint  at  base  of  bill.  There  are  traces  of  the 
three  fused  metatarsals  and  the  calcaneum  (?)  is  still  free.  In  the  young  Cormorant  the  nostrils  are  still  opeu,  the 
lachrymal  free.  The  occipital  style  is  represented  by  ligament  and  were  we  all  ignorant  of  its  existence,  it  night  readily 
be  overlooked.  The  hyoid  is  large.  It  would  seem  then  that  the  supramaxillary  does  not  appear  until  late  in  life  and 
it  may  have  no  morphological  meaning  ;  simply  it  ossifies  at  the  time  of  closing  of  nostrils.  The  occipital  style  of  7*. 
carunculatus  is  small  in  the  adult.  The  specimen  was  about  one  third  grown,  and  about  ten  days  old  probably. 

Sincerely  yours, 

FREDERIC  A.  LUCAS. 


204  MEMOIRS   OF   THE    CARNEGIE    MUSEUM 

cranium  proper  in  the  Man-o'-war-Bird  might  well  answer  for  that  of  an  Albatross 
but  slightly  removed  from  the  typical  stock.  Fregata,  however,  lacks  the  deep  supra- 
orbital  glandular  fossae  so  characteristic  of  the  Diomedeidze,  and,  from  above  down- 
wards, the  skull  is  somewhat  more  compressed  than  it  is  in,  for  example,  such  a 
species  as  the  Short-tailed  Albatross  (D.  albatrus)  (PI.  XXIX.,  Fig.  46). 

The  superior  mandible  is  broad  at  its  base,  and  tapers  gradually  forwards,  to  be 
armed  at  the  apex  with  a  powerful  and  decurved  hook  which  is  exceedingly  sharp 
at  the  point.  This  mandible  is  convex  from  side  to  side,  moderately  compressed, 
and  concave  longitudinally  along  the  mid-line  of  the  culmen,  from  the  cranium  to 
the  base  of  the  apical  hook  anteriorly.  The  narial  apertures  are  small  and  situate 
each  at  the  bottom  of  a  fossa-like  depression,  while  from  them  running  directly 
forwards,  one  upon  either  side,  is  a  distinct  groove.  It  is  rather  deep,  and  very 
narrow,  not  being  carried  upon  the  hooked  part  of  the  bill  at  its  distal  termination. 

No  distinct  cranio-facial  hinge  exists,  but  at  the  middle  point  in  that  region 
the  proximal  ends  of  the  premaxillaries  remain  unobliterated  throughout  life  (PI. 
XXIX.,  Fig.  46). 

Deeply  concave  towards  each  other,  and  with  sharpened  margins,  the  superior 
borders  of  the  orbits  are  separated  from  each  other  by  an  interval  of  something 
more  than  2  cm.  Mesially,  the  intervening  frontal  surface  shows  a  slight  eleva- 
tion, while  in  the  parietal  or  post-frontal  region  there  are  two  larger,  convex  and 
elongated  elevations  placed  side  by  side  with  a  median,  not  at  all  deep,  depres- 
sion passing  between  them.  Within  the  cranial  casket  these  elevations  harbor  the 
superior  surfaces  of  the  cerebral  hemispheres,  and  the  skull  is  thinner  there  than 
elsewhere  (PI.  XXIX.,  Fig.  46). 

The  crotaphyte  fossse  are  well-defined,  even  better  so  than  in  an  Albatross  (D. 
albatrus),  being  very  slightly  depressed  below  the  general  surface,  and,  in  the  mid- 
dle line  posteriorly,  do  not  meet  by  an  interval  of  a  centimeter  (PI.  XXIX.,  Fig.  45). 

Apart  from  this  character,  and  the  fact  that  the  squamosal  processes  are  more 
prominent  and  sharper  in  Fregata,  the  posterior  aspect  of  its  cranium  agrees  almost 
exactly,  character  for  character,  with  what  is  presented  to  us  on  that  view  in  the 
cranium  of  D.  albatrus.  In  this  I  do  not  exclude  the  pterygoids  and  quadrates. 

The  large  subvertical,  subcylindrical  foramen  magnum  is  partially  overarched 
by  the  well-defined  occipital  area,  and  the  condyle,  although  of  the  same  shape,  is 
not  quite  as  prominent  as  it  is  in  an  Albatross  (PL  XXIX.,  Fig.  48). 

Seen  upon  side  view,  we  are  to  note  the  deep  valley  of  the  temporal  fossa,  made 
so  by  the  large  outstanding  post-frontal  process  anteriorly  and  the  sharp,  ridge-like 
squamosal  projection  referred  to  above  (PI.  XXIX.,  Fig.  45). 


SHUFELDT  :     OSTEOLOGY    OF    THE    STKGANOPODES  205 

The  lacrymal  is  a  free  bone  articulating  by  its  upper  portion  with  the  free  border 
formed  by  the  frontal  and  nasal  bones,  while  its  descending  limb  is  bulbous  at  its 
lower  extremity,  and  fails  to  reach  quite  the  maxillary  below  it.  The  pars  plana 
is  nearly  aborted,  there  being  merely  a  small  bridge  of  bone  left,  that  arches  over 
the  anterior  end  of  the  nasal  nerve  as  it  enters  the  rhinal  chamber.  This  nerve 
passes  in  an  open  groove,  but  is  again  shielded  by  an  osseous  span,  just  as  it  enters 
the  orbit.  The  "foramen  rotundum"  is  large  and  is  distinct  from  a  still  more  exten- 
sive vacuity  which  is  seen  above  it  on  the  anterior  wall  of  the  cranial  casket.  No 
foramina  exist  in  the  interorbital  septum  proper.  Occasionally  a  small  distinct 
nerve  foramen  is  seen  to  the  outer  side  of  the  opening  for  the  exit  of  the  optic 
nerve.  The  anterior  border  of  the  mesethmoid  is  both  concaved  and  sharpened 
(PL  XXIX.,  Fig.  45). 

The  zygomatic  bar  is  quite  straight,  being  transversely  compressed  at  its  quadrato- 
jugal  end,  to  become  twisted  upon  itself  in  the  jugal  part,  and  so  vertically  flattened 
for  the  remainder  of  its  extent  or  in  the  maxillary  moiety.  The  extreme  anterior 
end  fuses  in  between  the  premaxillary  and  nasal.  At  the  hinder  extremity  we  find 
the  usual  little  peg  articulating  in  the  pitlet  on  the  outstanding  process  of  the 
quadrate  (PI.  XXIX.,  Figs.  45  and  48). 

As  has  already  been  remarked  above,  one  of  these  last-named  bones  bears  a 
very  close  resemblance  to  the  quadrate,  in  an  albatross.  The  orbital  process 
of  the  os  quadratum  in  Fregata  is  antero-posteriorly  compressed  just  as  it  is 
in  Diomedea,  and  its  free  extremity  is  expanded  and  finished  off  in  the  same 
manner. 

We  notice  a  slight  difference,  however,  in  the  form  of  the  internal  articular 
facet  of  the  mandibular  end  of  the  bone.  It  is  more  compressed  from  before,  back- 
wards in  Fregata,  and  the  articular  surface  presents  but  one  common  convexity, 
whereas  in  Diomedea  this  facet  is  impressed  by  a  deep,  oblique  valley,  the  axis  of 
which  is  parallel  to  the  pterygoid  of  the  same  side. 

As  in  the  Albatross,  a  pterygoid  bone  is  a  straight,  stout  element,  with  some- 
what enlarged  anterior  end,  and  a  markedly  expanded  posterior  one ;  in  the  last 
character  being  much  more  enlarged  than  it  is  in  Diomedea.  Both  birds  have  their 
pterygoids  pneumatic,  and  when  articulated  in  situ,  they  touch  each  other  in  the 
middle  line,  beneath  the  sphenoidal  rostrum. 

In  Fregata  the  basitemporal  region  is  small  and  of  a  triangular  outline ;  the 
eustachian  passages  are  very  open  canals,  and  their  anterior  beginnings  are  separated 
by  quite  an  interval  —  the  base  of  the  sphenoid  standing  distinctly  between  them 
(PI.  XXIX.,  Fig.  48). 


206  MEMOIRS   OF   THE    CARNEGIE    MUSEUM 

Although  morphologically  very  much  alike,  the  palatines  in  Fregata  fuse  together 
where  they  come  in  contact  with  each  other  posteriorly,  which  is  not  the  case  in  any 
Albatross  ever  examined  by  me.  The  ascending  and  descending  laminae  are  not  so 
powerfully  developed  as  they  are  in  the  Albatrosses,  but  in  Fregata  we  still  find  the 
broad,  horizontally  flattened  anterior  moieties  of  the  palatines,  with  the  mesial, 
elongated  and  narrow  interval  separating  them.  At  the  fore  part  of  this  we  like- 
wise see  the  maxillo-palatines,  similarly  separated,  with  their  external  borders  and 
surfaces  accurately  fused  with  the  contiguous  bones.  Between  them,  we  discover 
the  sharp  apex  of  the  extremely  slender,  and  long,  and  free,  and  curved  vomer  of  the 
Man-o'-war  Bird,  so  very  suggestive  of  being  an  extreme  modification  of  that  element 
as  we  found  it  to  exist  in  Diomedea.  (See  Figs.  16  and  17,  in  my  memoir  on  the  Oste- 
ology of  the  Tubinares  and  Steganopodes,  P.  U.  S.  N.  M.,  1888,  p.  279,  for  the  vomer 
in  an  Albatross.) 

The  postero-external  angle  of  a  palatine  in  Fregata  is  inclined  to  be  somewhat 
produced,  whereas  in  the  Diomedeidse  as  a  rule  that  angle  is  rounded  off  (PI. 
XXIX.,  Fig.  48). 

Upon  examining  the  mandible  in  Fregata  it  also  presents  a  number  of  characters 
it  has  in  common  with  that  bone  in  Diomedea.  In  form  it  is  a  long  V-shaped  struc- 
ture, with  truncated  postero-articular  ends.  The  rami  are  strong  and  thick;  the 
ramal  vacuities  are  closed  in;  the  rather  .meager  symphysisis  decurved  and  sharply 
pointed  at  the  apex.  Along  the  superior  margin  of  either  dentary  portion,  runs  a 
distinct  groove ;  these  borders  being  cultrate  in  the  Albatross,  and  the  aforesaid 
groove  being  conducted  down  upon  the  mesial  aspect  of  the  dentary  element,  where 
it  is  far  less  pronounced,  and  its  nature  not  so  marked.  The  mesial  aspect  of  either 
dentary  part  of  the  jaw  in  Fregata  is  also  deeply  grooved  for  nearly  its  entire  length ; 
this  last  groove  is  but  faintly  developed  in  Diomedea,  and  that  only  at  the  anterior 
third  of  the  bone  (PL  XXIX.,  Fig.  47). 

Fregata  has  a  more  pneumatic  mandible  than  Diomedea,  and  the  foramen  at 
either  articular  end  is,  in  the  former  genus  on  top  of  the  mesial  process,  while  in  the 
latter  it  is  situated  at  the  base  of  the  obliquely-disposed,  deep,  central  concavity,  or, 
in  other  words,  that  concavity  which  is  intended  to  accommodate  the  inner  large 
articular  facette  on  the  quadrate.  It  is  single  and  circular  in  either  case. 

Fregata  has  a  very  simple  skeleton  as  to  its  hyoidean  apparatus,  for  the  fore  part  is 
considerably  aborted,  while  behind  all  the  elements  do  not  ossify.  The  small  glosso- 
hyal  is  performed  entirely  in  elementary  cartilage,  and  only  the  diminutive  cerato- 
hyals,  which  are  distinct  from  each  other,  ossify.  The  short,  rather  bulky,  first 
basibranchial  ossifies,  but  there  is  no  sign  of  a  second  one.  Of  the  thyrohyal  ele- 


SHUFELDT  :     OSTEOLOGY    OF    THE    STEGANOPODES  207 

ments,  the  ceratobranchials  are  long,  slightly  curved,  and  completely  ossified ;  the 
epibranchials  are  in  cartilage  only.  In  my  specimen  the  sderotals  of  the  eye,  and 
the  bony  elements  of  the  internal  ear,  are  missing. 

Of  the  Remainder  of  the  Axial  Skeleton. 

Upon  examining  the  vertebral  chain  of  Fregata  aquila  we  find  in  it  thirteen 
vertebrae  in  the  cervical  region,  that  do  not  support  free  ribs ;  the  fourteenth 
vertebra  has  a  long,  slender  pair  that  are  without  unciform  processes,  the  next  five, 
all  freely  movable  upon  each  other,  connect  with  the  sternum  by  means  of  their 
costal  ribs  or  haemapophyses ;  then,  finally,  there  are  two  pairs  of  pelvic  ribs,  but 
it  is  only  the  costal  ribs  of  the  leading  or  anterior  pair,  that  connect  with  the 
sternum.  In  the  specimen  before  us,  we  may  call  them,  from  the  fifteenth  to  the  nine- 
teenth vertebra  inclusive,  true  dorsals,  while  counting,  as  best  we  may,  the  number 
of  vertebrae  fused  together  in  the  pelvic  sacrum,  there  appear  to  be  fourteen  in  all. 
Next  follow  six  free  caudals  and  a  large  pygostyle. 

Since  the  first  part  of  this  memoir  was  written  I  have  had  placed  before  me,  a 
skeleton  in  the  rough  of  the  Great  Wandering  Albatross  (D:exulans),  and  upon  com- 
paring the  arrangement  and  number  of  its  vertebrae  with  what  has  just  been  given 
for  Fregata,  we  find  it  to  be  dissimilar  in  many  particulars.  This  leads  me  to  think 
that  with  respect  to  the  spinal  column,  the  ribs,  and  the  vertebrae,  no  typical  Alba- 
tross will  be  found  to  agree  with  the  Man-o'-War  Bird. 

Pneumaticity  is  a  prominent  character  of  the  trunk  skeleton  of  Fregata,  and  it 
would  seem  that  all  the  bones  enjoyed  that  state.  The  atlas  has  a  broad  neural 
arch,  and  its  cup  instead  of  being  perforated,  is  extensively  notched  above.  On  the 
axis  the  "odontoid  process"  is  short  and  stumpy;  and  its  haemal  spine  is  also  an  in- 
significant affair.  On  the  dorsal  aspect  of  this  vertebra,  the  neural  spine  is  broad 
and  tuberous,  while  the  postzygapophysial  processes  are  much  swollen  also.  These 
latter,  in  the  third  vertebra,  are  joined  upon  either  side  with  the  prezygapophyses 
by  means  of  a  somewhat  delicate  interzygapophysial  bar.  A  large  haemal  spine  is 
present  here,  and  a  low  neural  one.  The  same  character  is  to  be  found  in  the  fourth 
vertebra,  and  both  third  and  fourth  possess  short  backward-projecting  parapophysial 
spines. 

In  the  fourth  or  fifth  cervical  a  distinct  neural  process  exists ;  it  is  absent  again 
to  include  the  ninth  vertebra;  it  is  but  faintly  developed  in  the  tenth,  and  from 
thence  backward  it  gradually  increases  in  proportion  and  changes  in  form,  until  we 
have  the  low,  quadrate  plate  of  the  dorsal  series.  Throughout  the  latter,  haemal 
spines  are  absent,  and  from  the  fifth  to  the  tenth  vertebra  inclusive,  the  carotid 


•JOS  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

canal  exists,  unclosed  as  it  is  by  the  rather  feebly  produced  parapophyses.  From, 
the  third  vertebra  to  the  thirteenth  inclusive,  lateral  vertebral  canals  are  to  be  found, 
and  in  the  fourteenth  vertebra  the  pleurapophysial  elements  free  themselves  as  a 
pair  of  ribs.  It  is  only  in  the  last  three  dorsals  that  metapophysial  spines,  of  no 
great  length,  extend  backward  from  the  postero-external  angles  of  the  transverse 
processes,  and  in  these  three  vertebrae,  upon  their  dorsal  aspects,  a  pneumatic  pit  is 
found,  on  either  side,  posterior  to  the  prezygayophyses.  The  mode  of  articulation 
among  the  centra  is  of  the  common  ornithic  character,  and  one  of  the  chief  features 
distinguishing  these  vertebrae  is  the  lack  of  prominence,  or  even  entire  absence,  of 
projecting  processes,  so  conspicuous  in  many  other  birds.  A  good  example  of  this 
is  seen  in  the  eighth,  ninth,  tenth  and  eleventh  vertebrae,  where  the  tendency  of  the 
short  parapophysial  processes  is  to  merge  with  the  centra  by  means  of  osseous 
bridges  connecting  the  two ;  and  another  is  the  marked  absence  of  haemal  spines. 

As  near  as  I  can  judge  from  my  specimen,  the  arrangement  of  the  ribs  of  Fregata 
is  as  follows :  On  the  fourteenth  vertebra  there  is  a  rudimentary  pair,  while  on  the 
fifteenth  there  is  a  long,  slender  pair  of  free  ribs,  that  are  without  epipleural  proc- 
esses. These  are  well-developed  on  the  succeeding  pair  belonging  to  the  sixteenth 
vertebra;  and  this  pair  of  ribs  are  the  first  of  the  series  to  connect  with  the  sternum, 
by  means  of  rather  short  haemapophyses,  the  ribs  of  the  dorsal  series,  seventeenth  to 
nineteenth  vertebrae  inclusive,  are  long,  very  narrow,  highly  pneumatic,  and  are 
characterized  by  the  unusual  length  of  their  epiplural  spines.  They  all  have  costal 
pairs  of  ribs,  gradually  increasing  in  length,  and  connecting  with  the  sternum. 

Two  pairs  of  pelvic  ribs  are  seen,  both  lacking  epipleural  appendages,  and  the 
ultimate  pair  anchylosed  with  the  vertebra  to  which  they  belong,  and  with  the  ven- 
tral surfaces  of  the  ilia.  The  last  pair  of  costal  ribs  fail  to  reach  the  sternum. 

The  pelvis  is  broad  and  flattened.  Anteriorly  oneientire  vertebra  projects  beyond 
the  ilia,  but  it  is  coossified  in  its  position  with  the  "sacrum." 

Viewed  from  above,  we  are  to  note  that  the  ilia  are  widely  separated  from  the 
sacral  crista,  which  latter  are  very  large,  rounded  and  depressed.  Slight  concavity 
characterizes  the  preacetabular  iliac  areas,  and  the  anterior  emarginated  borders  of 
these  bones  are  very  obliquely  truncated  from  their  antero-mesial  angles  backwards. 
The  interdiapophysial  vacuities  in  the  uro-sacral  region  are  of  considerable  size,  and 
the  most  part  they  have  a  parial  arrangement  and  are  very  large  in  front. 

The  postacetabular  areas  are  about  equal  in  extent  to  the  anterior  ones,  and  are 
convexed  as  much  as  the  latter  are  concaved.  Bony  fusion  between  the  ilia  and 
the  vertebrae  is,  in  all  this  region,  very  perfect,  extending  clear  to  the  sacral  ex- 
tremity, and  no  part  of  the  latter  projects  posteriorly  beyond  the  iliac  bones. 


SHUFELDT  :     OSTEOLOGY   OF   THE   STEGANOPODES 


Upon  lateral  view  of  this  pelvis  we  note  that  the  ischium  (upon  either  side)  is 
much  drawn  out  behind,  and  there  pointed.  It  may  he  said  that  hardly  any  ilio- 
ischiadic  notch  exists,  the  usual  site  for  it  being  very  shallowly  rounded  off.  For 
their  anterior  moieties  the  pubic  styles  are  very  slender,  but  their  elongated  pos- 
terior ends  are  more  clubbed  and  thickened,  where  they  come  simply  in  contact 
with  either  ischium  above  them.  On  the  lateral  aspect  the  antitrochanter  is  seen 
to  be  not  very  prominent ;  and  the  cotyloid  ring  and  ischiadic  foramen  have  their 
usual  ornithic  characters.  Posteriorly,  the  obturator  foramen  opens  most  com- 
pletely into  the  space  of  the  same  name  ;  thus,  in  reality,  merging  the  two  vacuities 
into  one.  In  the  capacious  pelvic  basin  on 
the  ventral  aspect  we  find  the  last  six  parap- 
ophysial  struts  of  the  vertebras,  when  pres- 
ent, very  distinct  and  slender,  being  thrown 
up  as  braces  in  the  usual  manner.  This  fea- 
ture also  obtains  with  all  the  vertebrae  at  the 
fore  part  of  the  sacrum,  and  indeed,  there  are 
only  two  in  the  series  that  entirely  lack  this 
development  of  the  parapophysial  processes, 
they  being  the  twenty-sixth  and  twenty- 
seventh  of  the  vertebral  chain  as  a  whole. 

This  pelvis  is  very  light  and  highly  pneu- 
matic; air-holes  always  occurring  in  a  small 
group  immediately  in  front  of  either  cotyloid 
ring,  as  well  as  in  many  other  places. 

Moreover,  in  many  respects  the  pelvis  in 
Fregala  is  a  very  differently  characterized 
bone  from  what  we  find  in  an  Albatross. 

In  the  skeleton  before  me,  I  find  six  large, 
free  caudal  vertebrse,  besides  a  big  parallelo- 
grammatic  pygostyle.  The  vertebrae  have 
very  long,  depressed,  narrow  diapophyses, 
the  anterior  and  posterior  borders  of  which  are  rounded  off.  Stumpy,  bifid, 
centrally  perforated  haemal  spines  are  found  only  in  the  last  two  or  three,  while  in 
all  these  vertebrae,  so  light  from  the  high  state  of  pneumaticity  they  enjoy,  the 
neural  spines  are  elevated  and  pointed.  The  neural  canal,  nowhere  very  large, 
seems  to  extend  even  into  the  pygostyle.  This  latter  bone  has  a  rounded  superior 
border,  while  below  and  behind  it  is  thickened  and  broadened.  At  its  lower  part 


FIG.  37.  Dorsal  aspect  of  the  pelvis  of  Fregata 
aqttila,  very  slightly  reduced.  From  a  photograph 
by  the  author  of  the  specimen  in  the  collection  of 
the  U.  S.  National  Museum  (No.  18485). 


.  :••'•*«•  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

it  is  usually  transversely  perforated  by  an  oval  foramen  of  some  size.  Above  its 
anterior  concave  articular  facet  the  margin  is  sharp,  the  corresponding  posterior  one 
being  rounded.  In  the  more  expanded  part  below  this  latter  margin,  we  find  the 
numerous  pneumatic  perforations  that  lead  into  its  interior  parts.  The  large 
pygostyle  of  an  Albatross  is  triangular  in  outline,  and  the  caudal  vertebrae  of  one 
of  these  birds  bear  but  slight  resemblance  to  those  bones  in  Fregata. 

A  number  of  anatomists  in  various  places  have  already  invited  attention  to  the 
striking  peculiarities  of  the  sternum  and  shoulder  girdle  of  the  species  we  here  have 
under  consideration  (PI.  XXX.,  Figs.  50  and  51). 

In  the  specimen  at  hand,  I  find  that  the  symphysis  of  the  furcula  is  extensively 
coossified  with  the  fore  part  of  the  carina  of  the  sternum,  while  its  upper  clavicular 
extremities  are  in  a  like  manner  very  completely  fused  with  the  mesial  aspects  of 
the  summits  of  the  coracoids,  upon  either  side.  The  sternal  ends  of  these  latter 
bones  form  free  articulations  with  the  sternum,  and  the  scapula?  are  also  freely  articu- 
lated each  with  the  corresponding  coracoid.  This  description,  it  will  he  seen,  differs 
from  what  Newton  found  in  a  specimen  of  Fregata,  and  he  says,  "  In  one  very  re- 
markable way  the  osteology  of  Fregata  differs  from  that  of  all  other  birds  known. 
The  furcula  coalesces  firmly  at  its  symphysis  with  the  carina  of  the  sternum,  and 
also  with  the  coracoids  at  the  upper  extremity  of  each  of  its  rami,  the  anterior  end 
of  each  coracoid  coalescing  also  with  the  proximal  end  of  the  scapula.  Thus  the 
only  articulation  in  the  whole  sternal  apparatus  are  where  the  coracoids  meet  the 
sternum,  and  the  consequence  is  a  bony  framework  which  would  be  perfectly  rigid 
did  not  the  flexibility  of  the  rami  of  the  furcula  permit  a  limited  amount  of  motion."2 

My  skeleton  is  from  an  adult  bird,  as  no  doubt  the  one  examined  by  Professor 
Newton  was,  and  this  makes  the  circumstance  all  the  more  remarkable. 

In  Albatrosses  the  symphysis  of  the  furcula  also  fuses  with  the  sternum,  while 
the  sternum,  coracoid,  and  scapulae  of  some  of  those  birds  bear  other  slight  resem- 
blances to  the  corresponding  bones  in  the  skeleton  of  the  Man-o'-war  Bird. 

Fregata  has  a  very  short  sternum,  being  about  as  long  as  it  is  broad.  The  body 
above  is  profoundly  concaved,  where  it  shows  numerous  pneumatic  foramina  espe- 
cially down  the  median  portion.  Either  costal  process  is  triangular,  pointed  and 
lofty,  and  the  costal  borders  short.  They  about  equal  in  length,  however,  on  either 
side,  the  sharp-edged  lateral  margin. 

The  rather  short  xiphoidal  processes  are  situated,  one  at  either  posterior-external 
angle  of  the  body  of  the  bone,  and  they  are  rounded  off  behind.  For  the  rest,  the 
xiphoidal  border  that  joins  them  is  nearly  an  unbroken  transverse  line,  exhibiting 

20  Alfred  Newton,  "  Dictionary  of  Birds,"  Art.  Frigate-Bird,  Part  I.,  pp.  293,  294,  London,  1893. 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES 


211 


neither  notches  or  indentations.  Ventrally,  the  carina  extends  the  entire  length  of 
the  bone,  its  lower  margin  being  very  convex  and  thickened  ;  the  lateral  edges  of  the 
latter  extending  beyond  the  sides.  The  anterior  carinal  boundary  is  sharp  and  short 
surmounted  above  by  a  rudimentary  manubrium.  Either  costal  groove  is  deep  and 
wide,  and  the  coracoids,  when  articulated  in  situ,  meet  in  the  median  line  above,  where 
they  separate  the  anterior  sternal  border  and  the  small  trihedral  manubrial  process. 

The  os  furcula  is  of  the  U-shaped  pattern,  and  is  coossified,  as  has  been  said,  with 
the  sternum  and  coracoid.  Its  rami  are  narrow  and  compressed,  with  its  l^poclei- 
dial  portion  below  very  broad,  triangular  in  outline,  slightly  concaved  in  front, 
and  withal  antero-posteriorly  compressed.  Above,  the  clavicular  ends  are  trans- 
versely very  thin.  Either  one  shows  two  places  of  bony  fusion  ;  one  at  the  tip,  and 
a  still  more  extensive  one  in  front  of  the  head  of  the  coracoid.  Mesiad,  between 
these,  there  exists  an  oval  foramen.  The  clavicular  extremities  are  separated  from 
each  other  by  a  distance  of  6  centimeters.  By  far  the  largest  bone  of  the  pectoral 
girdle  is  the  coracoid.  Either  one  of  them  has  a  height  of  8.5  cm.  with  a  large 
shaft  and  broad  sternal  end.  A  minute  epicoracoidal  process  is  present,  and  the 
clavicular  process,  although  pretty  well  developed  and  curving  forwards,  does  not 
reach  the  end  of  the  clavicle  by  quite  an  interval.  The  glenoid  cavity  faces  more 
than  usual  to  the  rear,  much  as  it  does  in  an  Albatross.  Measuring  on  its  chord,  a 
scapula  has  a  length  of  about  8  centimeters.  Its  inner  border  is  convex,  and  its 
outer  more  decidedly  concave.  For  its  middle  third,  the  bone  is  narrow  and  thick- 
ened, the  distal  extremity  being  slightly  dilated,  compressed  from  above  down- 
wards, and  brought  to  a  rounded  point  posteriorly.  Its  coracoidal  extremity  is 
also  much  compressed  in  the  vertical  direction,  very  wide  from  side  to  side,  with  its 
inner  angle  drawn  out  into  a  well-developed  process,  and  with  a  small  glenoidal 
facet  occupying  the  other  one. 

The  Pectoral  Limb. — The  bones  making  up  the  skeleton  of  the  upper  extremity 
are  all  completely  pneumatic,  and,  as  compared  with  those  of  the  pelvic  limb,  are 
chiefly  remarkable  for  their  enormous  comparative  lengths.  This  is  well  shown  in 
the  following  table  : 

Length  of  Humerus 21.0  cm. 

Femur 5. 7 

Ulna 27.5 

Tibio-tarsus 7.5 

Radius 26.6 

Fibula 6.5 

Carpo-metacarpus 13.0 

Tarso-metatarsus 2.4 

Index  digit 12.5 

Mid-anterior  toe 7.6 


212  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

The  humerus  presents  the  usual  double  sigmoidal  curve  seen  in  the  humeri  of 
almost  all  birds.  Its  shaft  is  smooth  and  subcylindrical  in  form,  being  somewhat 
compressed  from  side  to  side.  The  pneumatic  fossa  is  inclined  to  be  shallow  and 
the  foramina  in  it  very  small;  but  there  are  pneumatic  openings  in  other  parts  of 
the  bone,  notably  at  the  distal  extremity,  where  large  ones  occur  upon  either  aspect. 
The  radial  crest  or  the  crista  superior  is  very  prominent,  being  of  a  triangular  out- 
line, with  a  thickened  border  distad.  The  ulnar  tuberosity  or  the  crista  inferior  is  also 
conspicuously  developed,  with  the  tuberculum  internum  much  produced.  The  caput 
humeri  is  elongated  and  spindleform ;  it  is  separated  from  a  flat  tuberous  area  on  the 
ulnar  side  of  the  palmar  aspect  by  a  deep  transverse  sulcus,  the  sulcus  transversus. 
At  the  distal  end  of  the  bone  the  muscular  grooves  are  very  deep  on  its  anconal  as- 
pect, the  ulnar  side  apparently  much  raised  in  consequence.  A  deep  fossa  exists 
both  palmad  and  anconad  to  the  trochlefe.  A  low  ectepicondylar  eminence  is  pres- 
ent, with  deep,  circumscribed  muscular  pits  near  it  on  the  radial  border.  No  very 
special  resemblance  exists  between  this  bone  in  Fregata  and  the  humerus  as  it  is 
found  in  any  of  the  typical  Albatrosses.  The  same  would  seem  to  apply  to  the  re- 
mainder of  the  skeleton  of  this  limb. 

In  the  ulna  we  find  the  shaft  somewhat  more  cylindrical  than  it  is  in  the  humerus, 
and  presenting  but  a  very  slight  degree  of  curvature.  It  has  two  distinct  rows  of 
papillae  for  the  quill-butts  of  the  secondary  feathers,  the  more  prominent  row  being 
represented  by  eighteen  of  them.  The  concavities  for  the  trochlese  of  the  humerus  are 
deep  with  raised  edges,  but  the  olecranon  process  is  low  and  tuberous.  Its  distal  ends 
present  the  usual  ornithic  characters,  with  muscle-grooves  very  distinctly  marked. 

The  radius  viewed  upon  its  superior  aspect  presents  for  its  length  an  elongated 
sigmoidal  curve.  This  curve  for  its  distal  two  thirds  nearly  agrees  with  the  curva- 
ture of  the  shaft  of  the  ulna,  when  the  bones  are  articulated  in  situ ;  while  for  the 
proximal  third  it  is  reversed,  and  here  occurs  a  long,  narrow,  spindle-shaped  "  interos- 
seous  space."  The  radial  shaft  is  more  or  less  cylindrical,  smooth,  and  but  faintly 
marked  by  muscular  lines  or  ridges.  The  distal  end  of  the  bone  is  considerably 
expanded  in  the  transverse  direction,  and  here  pneumatic  foramina  are  to  be  seen. 
Its  proximal  head  is  only  moderately  developed,  and  it  is  the  middle  third  of  the 
continuity  of  the  shaft  that  possesses  the  greatest  caliber.  This  latter  very  gradually 
diminishes  as  we  approach  the  extremities. 

Fregata  when  adult  has  in  its  wrist  the  two  usual  carpal  segments,  which,  from 
the  high  state  of  pneumaticity  they  enjoy,  are  extremely  light.  Although  they  have 
the  usual  form  seen  in  birds,  they  are  here  powerfully  marked  by  the  various  mus- 
cular-grooves and  articular  facets  that  characterize  them. 


SHUFELDT  :     OSTEOLOGY   OF   THE   STEGANOPODES  213 

The  carpometacarpus  also  presents  us  with  the  common  ornithic  features  ;  though 
from  its  great  pneumaticity,  it  is  one  of  the  lightest  bones  of  its  size  we  have  ever 
met  with  in  the  class.  The  pollex  metacarpal  forms  a  large  triangular  projection 
at  its  usual  site,  while  the  shafts  of  the  index  and  medius  are  nearly  straight  and 
parallel  with  each  other ;  the  former  being  fully  six  times  the  bulk  of  the  latter. 
Distally,  neither  one  projects  beyond  the  other,  as  is  sometimes  the  case  in  birds  of 
other  groups. 

The  expanded  portion  of  the  proximal  phalanx  of  the  index  digit  is  both  per- 
forated and  riddled  with  pneumatic  foramina  of  various  sizes  and  shapes,  and  upon 
both  sides.  This  part  sends  down  a  conspicuous  rounded  process  beyond  the  proper 
shaft  of  the  bone,  while  from  the  antero-distal  aspect  of  the  shaft  itself,  a  similar 
process  projects  forward.  At  the  proximal  extremity  are  two  other  apophyses 
standing  out  from  the  bone,  one  being  upon  its  anconal  and  the  other  upon  its 
palmar  side,  while  the  plane  of  the  articular  surface  of  the  summit  extends,  to 
some  extent,  over  and  upon  each.  The  distal  or  terminal  phalanx  of  this  finger 
is  of  great  length  ;  trihedral  in  form  ;  and  much  scooped  out  posteriorly.  Pneu- 
matic foramina  enter  it  at  various  points,  one,  somewhat  elongated,  even  occurring 
at  its  apex.  The  pollex  digit  is  not  more  than  two  thirds  the  length  of  the  one 
just  described,  and  its  posterior  aspect,  instead  of  being  scooped  out,  is  very  sharp 
and  prominent ;  and  this  border  in  the  still  smaller  phalanx  of  the  medius  digit, 
has  upon  it  a  low  tuberous  apophysis  for  muscular  attachment.  None  of  these  ter- 
minal joints  of  the  fingers  appears  to  bear  claws  at  their  extremities. 

The  Pelvic  Limb.  —  Feebleness  of  a  very  marked  character  stamps  every  bone  of 
the  lower  extremity  in  Freyata.  The  skeleton  here  is,  moreover,  largely  non-pneu- 
matic. It  is,  apparently,  only  the  femur  and  proximal  moiety  of  the  tibio-tarsus 
that  enjoys  that  state  at  all.  The  former  bone  is  quite  as  pneumatic  as  the  humerus 
of  the  arm,  while  the  portion  of  the  tibio-tarsus  mentioned  appears  to  be  only 
moderately  so. 

The  femur  is  short  and  bulky,  with  its  head  very  distinctly  sessile,  and  its  upper 
part  markedly  scooped  out  for  the  insertion  of  the  round  ligament.  The  trochan- 
terian  ridge  does  not  rise  above  the  articular  summit  of  the  shaft,  and  it  is  broad 
and  flat  in  the  antero-posterior  direction  externally.  Below  these  parts  extends  the 
short,  straight,  cylindrical  shaft,  more  or  less  strongly  marked  by  the  usual  muscular 
lines.  The  condylar  portion  or  distal  end  is  weakly  developed,  though  all  the  char- 
acters common  to  the  femora  of  most  birds  are  present.  A  fibular  notch  is  well 
defined,  and  the  external  condyle  is  placed  lower  down  on  the  shaft.  Both  the 
popliteal  fossa  and  rotular  channel  are  very  shallow ;  the  latter,  it  may  be  said, 


214  MEMOIRS   OF   THE   CARNEGIE    MUSEUM 

hardly  exists  at  all.  Pneumatic  foramina  are  always  found  at  the  base  of  the 
former,  immediately  above  the  internal  condyle. 

Lack  of  salient  characters  distinguishes  the  tibio-tarsus  even  more  profoundly 
than  the  femur.  Its  cnemial  crest  and  processes  are  almost  completely  reduced,  the 
former  barely  rising  above  the  nearly  level  articular  summit  of  the  bone.  Com- 
paratively short  and  quite  straight,  its  shaft  is  of  decidedly  slender  bulk,  being 
subcylindrical  in  form.  The  fibular  ridge  is  confined  completely  within  the  limits 
of  its  upper  third,  being  but  a  little  more  than  a  centimeter  in  length.  Its  articu- 
lation with  that  bone  is  very  free.  At  the  distal  end  we  find  a  pretty  well  de- 
veloped pair  of  condyles,  but  the  osseous  bridgelet  in  front  is  low  down  and  weak, 
indicating  that  the  tendons  too,  which  it  is  intended  to  hold  in  place,  must  also  be 
but  feebly  developed. 

The  fibula  is  nearly  complete,  its  lower  end,  of  hair-like  dimensions,  is  fused  with 
the  side  of  the  shaft  of  the  tibio-tarsus  immediately  above  the  external  condyle  of 
the  latter  bone.  Above  its  proximal  articulation,  the  fibula  is  of  larger  size,  stand- 
ing in  strong  contrast  with  the  very  slender  straight  part  below  that  point. 

Fregata  has  a  flake-like  patella  of  some  size,  being  quadrilateral  in  outline,  and 
marked  obliquely  across  its  anterior  surface  by  a  groove  for  the  ambiens  muscle. 
As  with  the  vast  majority  of  birds,  it  is  non-pneumatic  in  character. 

The  tarso-metatarsus  is  wonderfully  short  and  thick-set.  This  bone  is  so  much 
abbreviated  in  the  direction  of  its  longitudinal  axis  that  it  hardly  appears  to 
possess  any  shaft  at  all.  Antero-posteriorly  it  is  flattened,  while  transversely  it  is 
relatively  broad.  On  its  anterior  surface  well-marked  grooves  plainly  indicate  the 
three  metatarsal  elements  of  which  it  is  composed,  while  posteriorly  the  short  shaft 
is  quite  flat  and  smooth.  Its  hypotarsus  is  bulky  and  circumscribed,  —  not  extend- 
ing down  the  bone,  —  while  a  single  central  canal  pierces  it  for  the  passage  of  the 
tendons.  This  is  of  some  size.  Distally,  the  trochlear  processes  are  comparatively 
large  and  spreading.  They  all  lie  in  nearly  the  same  transverse  plane,  the  inner 
one  being  the  lowest  in  position ;  the  outer,  the  highest ;  and  the  middle  one 
occupying  an  intermediate  place.  The  foramen  for  the  passage  of  the  anterior 
tibial  artery  is  peculiar,  inasmuch  as  its  lower  exit  is  in  the  sulcus  between  the 
outer  and  middle  trochlear  projections  instead  of  on  the  back  of  the  shaft  above 
that  point,  where  it  is  usually  to  be  found.  The  accessory  or  first  metatarsal  is  as 
large  in  proportion  as  in  those  birds  where  the  skeleton  of  this  limb  is  harmoniously 
developed  in  point  of  size  with  the  rest  of  the  osseous  system.  All  the  phalangeal 
joints  of  the  pes  are  well  developed,  being  arranged  upon  the  plan  of  2,  3.  4,  5,  for 
the  first  to  fourth  toe  respectively,  and  were  not  this  part  of  the  skeleton  of  the  foot 


SHUFELDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  215 

ridiculously  small  for  the  size  of  the  bird  to  which  it  belongs,  it  might,  with  truth, 
be  said  to  be  very  well  developed. 

The  ungual  joints  are  powerfully  curved,  and  considerable  curvature  character- 
izes the  majority  of  the  others,  especially  those  of  the  first,  second,  and  third  toes. 
Although  a  digression  from  the  consideration  of  the  osteology  of  Fregata,  it  is  inter- 
esting to  note  that  the  greatly  developed  podotheca  of  the  ungual  joint  of  the  middle 
toe  is  beautifully  pectinated,  — a  fact,  in  the  present  instance  at  least,  that  distinctly 
militates  against  the  view,  still  entertained  by  a  few  ornithologists,  that  the  function 
of  the  toes  of  birds  so  armed  is  the  possession  of  an  instrument  wherewith  they  may 
rid  themselves  and  their  plumage  of  vermin. 

Relationships  of  the  Steganopodes . 

If  we  base  our  judgment  on  the  osteology  of  the  birds  that  have  been  exam- 
ined in  the  present  memoir,  it  would  seem  that  we  are  justified  in  regarding  the 
Suborder  STEGANOPODES  as  being  composed  of  three  superfamilies.  These  may  be 
designated  as,  first,  the  Pelecanoidea ;  second,  the  Phaethontoidea ;  and  third,  and 
lastly,  the  Fregatoidea. 

Arranging  these,  and  arraying  the  existing  families  of  them,  with  their  genera, 
a  taxonomic  scheme  on  such  a  basis  would  stand  thus : 

SUPERFAMILIES.  FAMILIES.  GENERA. 

Pelecanus. 


Pelecanidse. 

Phalacrocorax. 
Pnalacrocoracidffl  ^T 

(  JNannopterum. 
Anhingidie. 

Anhmga. 


Pelecanoidea 


Sula. 

Phaethontoidea.         Phaethontidte.  Phaethon. 

Fregatoidea.  Fregatidse.  Fregata. 

The  genera  and  families  of  fossil  forms  are  not  taken  into  consideration  in  this 
scheme. 

Ornithotomists  are  agreed  that  the  Steganopodes,  constitute  a  well-defined  group, 
but  beyond  this  the  majority  are  reticent  as  to  the  question  of  the  affinities  existing 
among  the  families  and  genera  making  up  this  group,  and  the  relations  of  it  as  a 
whole  to  other  avian  groups  in  the  system. 

If  from  among  the  Phalacrocoracidse  we  select  the  genus  Phalacrocorax,  there  is 
no  doubt,  in  so  far  as  its  osteology  indicates,  that  it  is  closely  related  to  the  genus 
Anhinga.  This,  as  has  been  shown  above,  is  evident  from  a  direct  comparison  of 


216  MEMOIRS   OF   THE    CARNEGIE    MUSEUM 

the  corresponding  bones  of  the  skeleton  of  any  species  of  Cormorant  with  those  of 
the  skeleton  of  Anhinga. 

On  the  other  hand,  and  by  similar  methods,  there  is  no  disguising  the  kinship 
existing  between  Phalacrocorax  and  Sula,  although  the  gap  between  these  genera  is 
somewhat  greater  than  the  one  standing  between  the  Cormorants  and  the  Anhingas. 

Pelicans  of  the  genus  Pelicanus  are  aberrant  forms  which,  as  osteologically  indi- 
cated, have  varying  relations  with  all  three  genera  thus  far  mentioned.  They  are 
however,  apparently  more  nearly  related  to  Sulidse  than  they  are  to  the  Cormorants. 

From  the  Pelecanoidea  the  passage  to  the  Phaethontoidea  is  not  far  to  seek,  for 
upon  comparing  the  corresponding  bones  in  the  skeleton  of  such  a  Gannet  as  Sula 
brewsteri  with  those  of  Phaethon  flavirostris  we  are  at  once  confronted  with  so  many 
points  of  similarity  as  to  leave  no  doubt  in  our  minds  that  it  is  between  the 
genera  and  families  represented  by  such  species  as  these  that  the  linking  of  the  two 
groups  takes  place. 

This  is  important,  for  in  another  direction  we  are  led,  on  the  one  hand,  through 
Phaethon  to  the  suborder  LONGIPENNES,  and  on  the  other  to  the  suborder  TUBINARES; 
Phaethon  flavirostris  having  some  osteological  characters  that  strongly  suggest  larine 
affinities,  and  still  more  that  bring  to  mind  the  skeleton  of  a  Puffinus. 

Their  distinct  maxillo-palatines,  their  perforate  nostrils,  their  hardly  coalesced 
palatines,  their  four-notcheds  ternum,  and  their  ilia  widely  separated  from  the 
"sacral  crista,"  taken  in  connection  with  numerous  other  important  skeletal  char- 
acters, fully  entitle  the  Tropic  Birds  to  rank  as  a  superfamily  —  the  PIIAKTHON- 
TOIDEA  as  given  above. 

There  can  be  no  doubt  about  Fregata,  for  the  skeletal  characters  seen  in  its  skull, 
its  sternum  and  shoulder-girdle,  its  pelvis  and  limbs,  and  in  its  trunk  skeleton,  as 
we  have  in  detail  described  them  above,  stamp  it  at  once,  not  only  as  being  a  form 
having  many  skeletal  characters  completely  at  variance  with  those  found  in  average 
steganopodous  birds,  as  Cormorants  and  Gannets,  but  as  a  type  likewise  for  which 
a  superfamily  must  be  created,  in  order  to  show  that  these  striking  departures  are 
fully  appreciated  by  the  student  of  its  osteology.  As  indicated  in  our  scheme 
above,  this  superfamily  may  be  designated  as  the  FREGATOIDEA. 

The  pelvis  in  Fregata  is  decidedly  more  like  the  pelvis  in  Phaethon  than  in  other 
Steganopodes.  In  its  pelvic  limb-bones,  which  are  extraordinarily  short  and  otherwise 
weak,  as  compared  with  the  very  lengthy  pectoral  ones,  and  the  size  of  the  rest  of  the 
bird,  it  stands  quite  unique  in  the  suborder  to  which  it  belongs.  More  remark- 
able than  all,  however,  are  the  many  characters  in  its  skull,  which  powerfully  re- 
call the  Albatrosses  among  the  TUBINARES.  These  are  so  evident  that  one  is  almost 


SHUFELDT  :     OSTEOLOGY    OF   THE    STEGANOPODES  217 

led  to  believe,  if  it  be  not  actually  the  case,  that  the  strong-hooked  beak  in  the 
skull  of  Fregata  is  a  diomedean  character  rather  than  a  pelicanine  one.  Apart 
from  the  free  ends  of  the  furcula  coalescing  with  the  coracoids,  there  are  characters 
in  the  sternum  and  shoulder-girdle  of  Fregata  which  also  recall  the  forms  of  the 
corresponding  bones  in  the  Albatrosses,  but  beyond  this  there  appears  to  be  nothing 
else  in  the  skeleton  of  the  Man-o'-War  Bird  at  all  reminding  us  of  those  birds. 

As  this  relationship  exists  between  Fregata  and  Diomedea,  remote  as  it  may  be, 
it  nevertheless,  taken  in  connection  with  what  has  been  pointed  out  above  in  regard 
to  Pha'ethon  and  Puffinus,  ought  to  lead  us  to  believe  that  the  STEGANOPODES  are  more 
closely  affined  with  the  TUBINARES  than  they  are  with  the  LONGIPENNES. 

There  are  those  who  claim  to  see  a  kinship  existing  between  the  Accipitres  and 
the  FREGATOIDEA,  but  there  are  surely  no  indications  of  it  in  so  far  as  the  osteology 
of  any  of  the  representatives  of  the  two  suborders  in  question  are  concerned. 

ADDENDA. 

Since  writing  the  above  account  of  the  osteology  of  the  Steganopodes,  I  have  per- 
sonally reexamined  some  of  the  material  in  the  United  States  National  Museum, 
and,  thanks  to  the  marked  kindness  of  Mr.  F.  A.  Lucas,  the  able  Curator  of  the  De- 
partment of  Osteology  of  that  institution,  I  have  been  permitted  fully  to  examine 
and  compare  the  entire  collection  there,  constituting  as  it  does  the  finest  assortment 
of  material  illustrating  the  osteology  of  the  Steganopodes  in  existence.  A  number  of 
the  specimens  drawn  from  this  material  are  now  figured  for  the  first  time  in  the 
plates  to  the  present  memoir. 

To  what  I  have  already  set  forth  in  the  body  of  the  paper,  there  is  nothing  I  find 
in  particular  to  add  to  the  osteology  of  the  Phaethontidse  or  the  Sulidse.  Among  the 
Plotidse  (the  Anhingidsn  of  the  A.  O.  U.  "Check-List ")  I  examined  a  skeleton  of  Plotus 
levaillanti,  and  it  presents  all  the  usual  characteristics  of  the  skeleton  in  that  family 
of  birds.  A  dorsal  view  of  its  pelvis  is  given  in  Plate  I.,  Fig.  1,  which  will  assist  in 
illustrating  what  I  have  said  in  the  body  of  the  memoir  in  regard  to  the  skeleton 
of  P.  anhinga.  I  have  never  had  the  opportunity  to  examine  the  skeletons  of  the 
two  other  known  species  of  this  family.  (Sharpe's  "Hand-List  of  Birds,"  p.  236.) 

The  collection  of  Cormorant  skeletons  (Phalacrocoraddie)  in  the  U.  S.  National 
Museum  is,  as  I  have  said  above,  the  finest  in  the  world  at  the  present  writing, 
nearly  every  known  species  being  represented.  It  is  Mr.  Lucas'  intention,  some- 
time in  the  future,  I  understand,  to  monograph  this  group,  and  it  will  be  a  very 
valuable  contribution  to  the  subject.  Their  skulls  present  some  very  interesting 
variations,  and  the  majority  of  these  are  well  shown  in  the  figures  of  the  Plates 


218  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

illustrating  this  memoir  (Plate  IV.,  Figs.  13-21  and  Plate  VI.,  Figs.  25,  27  and  29). 
They  not  only  vary  in  size  according  to  the  species,  but  perhaps  the  most  interest- 
ing variation  they  offer  is  the  marked  vertical  compression  of  the  skull  they  exhibit, 
associated,  as  it  is,  with  a  decided  elongation  and  narrowness  of  that  part  of  the 
skeleton.  This  is  well  seen  in  such  a  species  as  Phalacrocorax pelagicus  robustus,  where 
this  character  about  reaches  its  maximum.  At  the  other  extreme,  we  find  the  skull 
of  some  Cormorants  to  be  moderately  shortened,  with  a  broad,  dome-like  cranium, 
.which  admits  of  an  unusually  capacious  brain  cavity.  A  species  having  this  char- 
acter markedly  exemplified  is  Phalacrocorax  albiventris,  and  its  skull  is  shown  in 
Plate  IV.,  Figs.  14  and  21,  and  in  Plate  VI.,  Fig.  29.  A  good  medium  type  stand- 
ing between  these  two  extremes  is  seen  in  Phalacrocorax  dilophus,  while  all  the  other 
species  of  Cormorants  tend  either  toward  P.  p.  robustus,  or  toward  P.  albiventris  in  the 
matter  of  this  flatness  and  elongate-narrowness  of  their  skulls,  or  in  the  shorter, 
broader  and  more  capacious  cranium  of  the  last-named  species.  The  shading  either 
way  is  often  so  gradual  that  everything  else  being  equal,  it  hardly  seems  to  offer 
justifiable  grounds  for  generic  divisions.  Associated  with  these  forms  of  the  skull 
in  the  Cormorants,  we  are  to  note  the  variation  in  the  form  of  the  pterygoid  bones 
at  the  inferior  aspects  of  the  same.  Some  Phalacrocoracidse  possess  long  and  com- 
paratively slender  pterygoids,  while  other  species  have  them  much  shorter  and 
stouter.  Phalacrocorax  p.  robustus  is  an  excellent  example  of  the  first  of  these  (Plate 
VI.,  Fig.  28),  while  P.  albiventris  well  exhibits  the  last-named  condition,  while  in 
P.  dilophus  again,  they  are  moderately  elongated  and  fairly  stout,  thus  once  more, 
affording  an  example  of  the  medium  type  in  this  particular.  In  some  Cormorants 
the  mesethmoid  bone  is  not  perforated  by  a  large  median  vacuity,  as  is  seen  to  be 
the  case  in  others.  It  is  thus  perforated  in  such  species  as  P.  p.  robustus  and  P.  albi- 
ventris, while  it  is  perfectly  solid  in  such  forms  as  P.  dilophus  and  P.  melanolcucus. 
There  are  also  interesting  differences  to  be  noted  in  the  comparative  size  and  form 
of  the  foramen  magnum,  the  morphology  of  the  cranio-facial  hinge,  and  other 
minor  points,  the  majority,  of  which,  if  of  any  importance,  are  noticed  in  the  body 
of  the  present  memoir. 

The  pelvis  in  the  various  species  of  the  Cormorants  also  exhibits  a  difference  in 
form.  In  P.  pelagicus,  for  example,  it  is  comparatively  short,  narrow,  and  with  the 
ilio-ischiatic  notch  not  very  deep,  while  in  Graculus  Carbo,  it  is  much  elongated, 
narrow,  and  the  aforesaid  notch  very  deep.  Other  species  of  the  Phalacrocoracidse 
tend  one  way  or  the  other  in  this  particular.  The  short-bodied  Cormorants  have 
the  sternum  more  or  less  broad  and  short,  while  in  the  long-bodied  species  this  bone 
is  likewise  more  elongated  and  narrower. 


SHUFKLDT  :     OSTEOLOGY    OF   THE   STEGANOPODES  219 

As  I  have  shown  in  this  memoir  all  Cormorants  possess  a  big  patella.  Mr. 
Lucas  in  studying  this  bone  has  observed  that  this  sesamoid  in  some  of  the  species 
is  perforated  for  the  passage  of  the  ambiens  muscle,  while  in  others  it  is  not  so,  but 
this  perforation  is  not  associated  with  other  characters  in  such  a  manner  that  the 
condition  can  be  regarded  as  having  any  taxonomic  value.  Mr.  Lucas  at  my 
request  kindly  examined  this  point  for  me  in  quite  a  number  of  species  of  Cor- 
morants, and  found  that  the  patella  is  thus  perforated  for  the  ambiens  in  Graculus 
Carbo,  Phalacrocorax  dilophus,  P.  vigua,  P.  harrisi,  P.  Magellanicus,  P.  albiventris, 
(where  it  is  small)  and  in  P.  pelagicus,  while  the  patella  is  imperforate  in  Phalacro- 
corax melanoleucus,  P.  pimctalus,  P.  penicillatus  and  P.  urile. 

Osteologically,  the  Pelecanidse  constitute  quite  a  homogeneous  group  of  birds, 
and  certainly  a  thoroughly  circumscribed  family  of  the  Steyanopodes.  I  have  ex- 
amined the  skeleton  in  several  species,  but  more  particularly  in  the  case  of  Pelecanus 
sharpei,  P.  fuscus,  P.  onocrotalus,  and  P.  erythrorhynchus.  In  some  species  the  mandi- 
bles are  broad  and  comparatively  shorter  than  they  are  in  others,  and,  when  so,  they 
are  compressed  from  above  downwards.  This  is  the  case  in  P.  sharpei  (Plate  VII., 
Figs.  36,  37),  and  in  this  species  we  note  in  its  skull  that  upon  the  lateral  aspect  of 
the  superior  mandible,  just  where  it  is  joined  to  the  maxillary  bone,  the  compact 
tissue  is  continuous  downwards  to  the  anterior  end  of  the  corresponding  palatine, 
completely  overlying  and -concealing,  on  side  view,  the  spongy  tissue  of  bone  in  the 
rhinal  chamber,  (Fig.  37).  Whereas  in  such  a  species  as  P.  fuscus  there  is  a  large 
triangular  interval  left  open  here,  so  that  upon  the  same  view  we  are  enabled  to  see 
almost  the  entire  mass  of  the  osseous  spongy  tissue  of  the  aforesaid  space,  (see  Fig. 
40  of  my  memoir,  "  Observations  upon  the  Osteology  of  the  Order  Tubinares  and 
Steganopodes,"  Proc.  U.  S.  Nat.  Mus.,  1888,  p.  312).  In  the  drawing  referred  to 
the  upper  and  lower  edges  of  the  united  palatines  have  been  shaved  off,  but  I  was 
quite  a  juvenile  osteologist  when  I  prepared  that  specimen  ;  indeed  it  was  my  first 
osteological  preparation  (1864).  The  correct  form  and  outline  of  the  lower  united 
edge  of  the  palatine  bones  is  shown  in  the  case  of  P.  sharpei  in  Plate  VII.,  Fig.  37, 
of  the  present  memoir.  In  Figs.  35  and  40  of  that  plate  I  would  say  that  the 
horny  podotheca  covering  the  superior  mandible  of  Pelecanus  fuscus  has  only  in  part 
been  removed,  and  this  also  applies  to  the  anterior  two  thirds  of  the  mandible  shown 
in  Fig.  41.  Beyond  what  has  been  mentioned  above,  in  most  other  respects,  the 
skulls  of  P.  fuscus  and  P.  sharpei  are  very  much  alike. 

In  the  mandible  the  ramal  symphysis  is,  for  the  size  of  the  bone,  altogether  the 
weakest  union  of  any  in  the  entire  Class  Aves.  For  example,  the  ramus  of  the  jaw 
in  P.  sharpei  has  a  length  of  34.5  centimeters,  while  the  symphysis  joining  the  two 
rami  together,  anteriorly,  measures  but  3  millimeters  in  any  direction. 


220      '  MEMOIRS    OF   THE    CARNEGIE    MUSEUM 


EXPLANATION  OF  PLATES. 

(All  the  specimens  figured  in  the  Plates  (XX I.-XXX.)  are  reproductions  of  photographs  made 
by  the  author,  the  material  being  in  either  his  own  private  collection,  or  the  collection  of  the 
United  States  National  Museum.) 

PLATE  XXI.  Fig.  1.  Dorsal  aspect  of  the  pelvis  of  Plotus  levaillanti.  Adult.  (Coll.  U.  S. 
Nat.  Museum  No.  18,743.)  Two  of  the  pelvic  ribs  show  upon  the  right  side. 
Somewhat  reduced ;  the  mid-longitudinal  line  of  this  bone  measures  9.5  cm. 
not  including  the  ossified  anterior  tendinal  extensions. 

Fig.  2.  Basal  view  of  the  skull  of  Phaethon  cethereus,  adult,  mandible  removed, 
slightly  reduced.  Specimen  in  author's  collection.  From  the  island  of  Sail 
Pedro  Martis,  Gulf  of  California.  Collected  in  April,  1889. 

Fig.  3.  Superior  aspect  of  the  skull  of  Phaethon  Jlavirostris,  adult.  (Coll.  U. 
S.  Nat.  Musum  No.  17,841.)  Slightly  reduced,  the  reduction  being  propor- 
tionate in  amount  with  the  skull  shown  in  Fig.  2. 

Fig.  4.  Skeleton  of  left  foot  of  Fregata  aquila,  adult.  (Coll.  U.  S.  Nat. 
Museum,  No.  18,485.)  Somewhat  reduced.  Sheath  left  on  midanterior  toe 
shows  the  "  pectinated  claw." 

Fig.  5.  Ventral  view  of  the  sternum  of  Phaethon  cethereus,  adult  (author's 
collection).  Very  slightly  reduced.  Collected  in  April,  1889.  San  Pedro 
Martis  Isle,  Gulf  of  California.  The  skull  in  Fig.  2  and  this  sternum  are 
from  two  different  individuals. 

Fig.  6.  Left  lateral  aspect  of  the  trunk  skeleton  of  Phaethon  Jlavirostris,  adult. 
(Coll.  U.  S.  Nat.  Museum,  No.  17,841.)  Very  slightly  reduced.  The  skull 
shown  in  Fig.  2  belonged  to  this  skeleton,  but  the  reduction  in  the  former  is 
somewhat  greater. 

PLATE  XXII.  Fig.  7.  Right  lateral  view  of  the  skull  and  mandible  of  Sula  gossi,  adult 
female  (author's  collection).  Very  slightly  enlarged.  Mandible  detached. 
The  superior  mandible  is  tubular  at  the  extremity  and  pervious  at  the 
apex.  Collected  at  San  Pedro  Martis  Island,  Gulf  of  California,  16 
Oct.,  1888. 

Fig.  8.  Basal  view  of  the  skull  of  Sula  gossi,  adult  female  (author's  collec- 
tion). Very  slightly  reduced.  Collected  at  same  time  and  place  as  the  speci- 
men shown  in  Fig.  7. 

Fig.  9.  Basal  view  of  the  skull  of  Sula  Brewsteri.  Same  specimen  as  shown  in 
Fig.  7.  Very  slightly  reduced.  Left  pterygoid  bone  dislocated  inwards  to 
show  the  form  of  the  corresponding  quadrate. 


SHUFELDT  :    OSTEOLOGY    OF   THE   STEGANOPODES 


221 


PLATE  XXIII.    Fig.  10.  Superior  aspect  of  the  skull  of  Sula  tjossi.     Mandible  removed.     Same 

specimen  as  the  one  shown  in  Plate  II.,  Fig.  8.     Very  slightly  reduced. 
Fig.  11.   Superior  aspect  of  the  skull  of   Sula  brewsteri.     Mandible  removed. 
Same  specimen  as  the  one  shown  in  Plate  II.,  Fig.  9.     Very  slightly  reduced, 
and  in  the  same  proportion  as  the  skull  shown  in  Fig.  10. 

Fig.  12.  Left  lateral  view  of  the  trunk  skeleton  of  Sula  gossi.  Reduced  one 
third.  Belonged  to  the  same  individual,  which  furnished  the  skull  shown  in 
Fig.  10. 

PLATE  XXIV.  (All  the  bones  figured  in  this  plate  are  from  the  Coll.  U.  S.  Nat.  Mus.  and  their 
numbers  are  shown  upon  the  specimens.  They  are  all  adult,  and  natural 
size.) 

Fig.  13.  Left  lateral  view  of  the  skull  of  Phalacrocorax  pelagicus  robustus. 

Mandible  removed.     (See  Fig.  18.) 

Fig.  14.  Left  lateral  view  of  the  skull  of  Phalacrocorax  albiventris.    Man- 
dible removed.     (See  Fig.  21.) 
Fig.  15.  Left  lateral  view  of  tfie  skull  of  Phalacrocorax  urile.     Mandible 

removed.     (Specimen  bears  no  number.) 

Fig.  16.  Basal  view  of  the  skull  of  Phalacrocorax  melanoleucus.     Mandi- 
ble removed  (Australia).     There  is  but  one  known  species  of  cormorant  in 
the  world  smaller  than  this  one. 
Fig.  17.  Left  lateral  view  of  the  skull  and  mandible   of   Phalacrocorax 

dilophus.     Mandible  detached.     (See  Fig.  19.) 

Fig.  18.  Superior  aspect  of  the  skull  of  Phalacrocorax  p.  robustus.  Mandi- 
ble removed.  (See  Fig.  18.) 

Fig.  19.   Superior  aspect  of  the  skull  of  Phalacrocorax  dilophus.     Mandi- 
ble removed.     (See  Fig.  17.) 
Fig.   20.   Superior    aspect   of    the   skull   of    Phalacrocorax  melanoleucus. 

Mandible  removed.     (See  Fig.  16.) 

Fig.  21.  Superior  aspect  of  the  skull  of  Phalacrocorax  albiventris.  Man- 
dible removed.  (See  Fig.  14.) 

This  series  of  specimens  is  designed  to  show  the  marked  variation  in  form 
of  the  skull  among  the  cormorants  (Phalacrocoracidce),  ranging  all  the 
way  from  the  much  vertically  compressed  skull  of  P.p.  robustus  (Fig.  13) 
to  the  lofty  skull  of  P.  albiventris  (Fig.  14). 

PLATE  XXV.      Fig.  22.  Dorsal  view  of  the  trunk  skeleton  of  Phalacrocorax  urile.  with  chain 
of  cervical  vertebrae  naturally  articulated  but  curved  far  backward  and  to  the 
right.     Reduced  one  half.     The  skull  shown  in  Fig.  15  belonged  to  this  skeleton. 
Fig.  23.   Left  lateral  view  of  the  trunk  skeleton  of  Phalacrocorax  urile.     Re- 
duced one  half,  and  the  same  specimen  as  shown  in  Fig.  22. 


222  MEMOIRS   OF   THE   CARNEGIE   MUSEUM 

PLATE  XXVI.  Fig.  24.  Anconal  aspect  of  the  right  carpo-metacarpus  of  Freyata  aquila  (Spec- 
imen No.  18,485,  Coll.  U.  S.  Nat.  Museum).  Adult.  Reduced  ;  the  actual  ex- 
treme length  of  the  bone  being  13.2  cm. 

Fig.  25.  Left  lateral  view  of  the  skull  of  Phalacrocorax  melanoleuctis.  Man- 
dible removed.  Natural  size.  Same  skull  as  shown  in  Plate  IV.,  Fig.  20. 

Fig.  26.  Anconal  aspect  of  the  proximal  phalanx  of  the  medius  digit  of  the 
maims  of  the  right  pectoral  limb  of  Freyata  aquila.  Slightly  reduced.  From 
the  same  skeleton  that  the  bone  shown  in  Fig.  24  was  obtained,  with  which 
it  was  distally  articulated. 

Fig.  27.  Basal  aspect  of  the  skull  of  Phalacrocorax  dilophns.  Natural  size. 
Same  skull  as  the  one  shown  in  Fig.  17,  Plate  IV. 

Fig.  28.  Basal  aspect  of  the  skull  of  Phalacrocorax  p.  rooustus.  Natural  size. 
Same  skull  as  the  one  shown  in  Fig.  13,  Plate  IV. 

Fig.  29.  Basal  aspect  of  the  skull  of  Phalacrocorax  albiventris.  Natural  size. 
Same  skull  as  the  one  shown  in  Fig.  21,  Plate  IV.  Note  how  much  shorter 
the  pterygoid  bones  are'  in  this  species  as  compared  with  the  corresponding 
elements  in  the  skulls  shown  in  Figs.  27  and  28.. 

Fig.  30.  Dorsal  aspect  of  the  sternum  and  os  furcula  of  Phalacrocorax  aloi- 
ventris  (No.  18,437,  Coll.  U.  S.  Nat.  Museum).  Eeduced  about  one  fifth. 
(See  Fig.  21,  Plate  IV.  Both  from  the  same  bird.) 

PLATE  XXVII.  (Pelecanus  sharpd  and  Pelecanus  fuscus.  Adults.  All  less  than  half  natural 
size.  P.  sharpei  is  No.  18,736  of  the  Collection  in  the  U.  S.  Nat.  Museum, 
and  P.  fuscns  (author's  collection)  was  shot  by  me  on  Indian  Cay,  Bahama 
Banks,  in  1864.) 

Fig.  31.  Anconal  aspect,  right  ulna,  Pelecanus  sharpei. 

Fig.  32.  Anterior   aspect,  left   femur,  .P.  sliarpei.     Same  specimen  as  Fig. 

31  and  the  others  on  the  Plate. 

Fig.  33.  Anterior  aspect  of  the  left  tibio-tarsus,  P.  sharpei. 
Fig.  34.  Palmar  aspect  of  left  humerus,  P.  sharpei. 
Fig.  35.  Basal  view  of  the  skull  of  P.  fuscus  ;  mandible  removed. 
Fig.  36.  Basal  view  of  the  skull  of  P.  sharpei ;  mandible  removed. 
Fig.  37.  Left  lateral  view  of  the  skull  of  P.  sharpei  ;  mandible  removed. 
Fig.  38.   Anterior  aspect  of  the  right  coracoid  ;  P.  sha.rpei. 
Fig.  39.  Anconal  aspect  of  the  left  carpo-metacarpus,  P.  sharpei. 
Fig.  40.   Superior   view  of  the  skull   of  P.  fuscus  ;    mandible  removed ; 

same  specimen  as  Fig.  35,  and  the  mandible  shown  in  Fig.  41. 
Fig.  41,     Superior  view  of  the  mandible  of    P.  fuscus.     (See  Fig.  40.) 
The  three  bits  of  wax  supporting  this  bone   show  beneath   the   articular 
cups  and  the  symphysis. 


SHUFELDT  :    OSTEOLOGY    OF   THE   STEGANOPODES 


223 


PLATE  XXVIII.  Fig.  42.  Dorsal  aspect  of  the  sternum  and  the  coossified  os  furcula  of  Pelecanus 
sharped;  reduced  about  one  fifth.  No.  18,736,  Collection  in  the  U.  S.  Nat. 
Museum.  See  Figs.  31,  32  and  others  of  Plate  VI.  Same  skeleton. 

Fig.  43.  Palmar  aspect  left  pectoral  limb  of  Phalacrocorax  umle.  Reduced 
about  one  fourth.  From  the  same  skeleton  that  furnished  the  skull  shown  in 
Fig.  15,  Plate  IV.,  and  the  trunk  skeleton  shown  in  Figs.  22  and  23,  PI.  V. 

Fig.  44.  Inner  aspect  of  the  right  pelvic  limb  of  Phalacrocorax  wile.  Reduced 
about  one  fourth  from  the  same  skeleton  that  furnished  the  pectoral  limb 
shown  in  Fig.  43. 

PLATE  XXIX.     (Skull,  including  mandible  of  Fregata  aquila.     No.  18,485  of  the  Coll.  U.  S. 
Nat.  Museum.     Adult.     All  slightly  reduced  ;  Fig.  46  more  so  than  the  others.) 
Total  length  of  skull  17.3  centimeters,  and  ramus  of  mandible  16.5  cm. 
Fig.  45.  Left  lateral  view  of  the  skull ;  mandible  detached. 
Fig.  46    Superior  view  of  the  skull ;  mandible  removed. 
Fig.  47.  Superior  view  of  the  mandible. 

Fig.  48.  Basal  view  of  the  skull ;  mandible  removed.  For  other  bones  of 
the  skeleton  of  this  individual  see  Plate  I.,  Fig.  4;  Plate  VI.,  Figs.  24,  26  ; 
Plate  X.,  Figs.  50  and  51.  In  Fig.  48  the  right  quadrate  bone  and  the 
pterygoid  of  the  same  side  have  been  removed. 

PLATE  XXX.  Fig.  49.  Ventral  aspect  of  the  pelvis  of  Pelecanus  sharpei;  considerably  re- 
duced. The  longitudinal  median  line  of  the  vertebral  portion  of  this  bone 
measures  about  19.5  cm.  It  is  from  the  same  skeleton  that  furnished  the 
bones  shown  in  Plate  VII. 

Fig.  50.  Ventral  aspect  of  the  sternum  and  shoulder-girdle  of  Fregata  aquila; 
slightly  reduced.  See  remarks  under  Fig.  48,  PI.  IX. 

Fig.  51.  Left  lateral  aspect  of  the  sternum  of  Fregata  aquila.  Natural  size. 
See  remarks  under  Plate  IX.  and  Fig.  48. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXI. 


SHUFELDT.    OSTEOLOGY  OF  THE  STEGANOPODES.    PLATE  I. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXII. 


fy.9. 


SHTJFELDT.    OSTEOLOGY  OF  THE  STEGAXOFODEB.    PLATE  II. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXI II. 


fy.<o. 


SHUFELDT.     OSTEOLOGY  OP  THE  STEGANOPODES.     PLATE  III. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXIV. 


SHUFELDT.    OSTEOLOGY  OF  THE  STEGANOPODES.    PLATE  IV. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXV. 


SHUFELDT.     OSTEOLOGY  OF  THE  STEGANOPODES.     PLATE  V. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXVI. 


SHUFELDT.     OSTEOLOGY  OF  THE  STEGANOPODES.     PLATE  VI. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXVII. 


fy  37. 


SHUFELDT.     OSTEOLOGY  OF  THE  STEGANOPODES.     PLATE  VII. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXVIII. 


SHUFELDT.     OSTEOLOGY  OF  THE  STEGANOPODES.     PLATE  VIII. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXIX 


SHUFELDT.    OSTEOLOGY  OF  THE  STEGANOPODES.     PLATE  IX. 


MEMOIRS  CARNEGIE  MUSEUM,  VOL.  I. 


PLATE  XXX. 


A- si- 


SHUFELDT      OKTKOI.OOY  OK  THE  STEGANOPODES.     PLATE  X. 


14  DAY  USE 

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